Processes and intermediates for the preparations of isomer free prostaglandins

ABSTRACT

Novel processes for the preparation of a compound of Formula I-2 substantially free of the 5,6-trans isomer: 
     
       
         
         
             
             
         
       
     
     wherein 
     
       
         
         
             
             
         
       
     
     R 2 , R 3  and R 4  are as defined in the specification are provided. Novel intermediates for the preparations of isomer free Prostaglandins and derivatives thereof are also provided.

CROSS REFERENCE APPLICATIONS

This application is a Divisional of U.S. patent application Ser. No.14/802,072 filed Jul. 17, 2015, which is a Divisional of U.S. patentapplication Ser. No. 13/967,473 filed Aug. 15, 2013, the contents ofwhich are incorporated herein by reference.

FIELD OF THE INVENTION

The present invention relates to novel processes and intermediates forthe preparations of isomer free Prostaglandins and the derivativesthereof.

BACKGROUND OF THE INVENTION

Prostaglandin ester analogues of the following Formula I-2

wherein

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl; and R₄ is C₁₋₇-alkyl, such as, Latanoprost, Isoproylunoprostone, Isoproyl cloprostenol, Travoprost and Tafluprost have beenused in the management of open-angle glaucoma. The Prostaglandin esteranalogues of Formula I-2 have been shown to have significantly greaterhypotensive potency than the parent compound, presumably as a result oftheir more effective penetration through the cornea. They reduceintra-ocular pressure by enhancing uveoscleral outflow, and may alsohave some effect on trabecular meshwork as well.

As shown in the following Scheme A:

most of the Prostaglandin ester analogues of Formula I-2 disclosed inthe prior art, such as in WO02096898, EP1886992, EP2143712,JP2012246301, U.S. Pat. No. 6,720,438, US2008033176, WO2010097672, andU.S. Pat. No. 7,582,779 were obtained by first synthesizing a LactoneVIII, wherein

or is a protective group of carbonyl group; P₁ and P₂ are protectivegroups for the hydroxyl groups;

is a singe or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl and then conducting a semi-reduction of the Lactone to geta Lactol VII which was underwent a Wittig reaction to produce a C5˜C6configuration cis-olefin of Formula IV-1, which was then converted toProstaglandin ester analogues of Formula I-2. No matter which kind ofWittig reagents or solvents were used or what was the temperature forthe Wittig reaction, it was inevitable that about 2˜10% 5,6-trans isomerof the compound of Formula IV-1 would be produced. If the startingmaterial already contained a trace amount of an isomer (e.g., 15β-isomeror enantiomer), the resultant compound of Formula IV-1 would contain thecorresponding isomer.

As shown in the following Scheme B:

some of the syntheses of Prostaglandin ester analogues of Formula I-2,for example, latanoprost disclosed in the prior art, such as WO02090324and US2009259058, were involved a conjugate addition of a cyclopentenoneVI′ with a ω-side chain unit IX′ to obtain a cyclopentanone V-2′, whichwas then underwent a 9-keto reduction to get a protected latanoprostIV-2′. Nevertheless, such a conjugate addition could not avoid thegeneration of a trace amount of 8β-isomer and 12α-isomer, nor could itavoid the generation of a trace amount of 9β-isomer. In addition,commercially available cyclopentenone VI′ and ω-side chain unit IX′ verylikely contain trace amount of enantiomers and as a result, in thereaction of Scheme B, the 15β-isomer of latanoprost would be produced.Moreover, commercially available cyclopentenone VI′ could contain atrace amount of 5,6-trans isomer and as a result, in the reaction ofScheme B, the 5,6-trans isomer of the latanoprost would be produced.

As shown in the following Scheme C:

WO2011008756 discloses the synthesis of Travoprost by a ring-closingreaction with the cyclopentane ring at the presence of a Grubb'scatalyst, and conducting deprotection and ring-opening reactions toobtain Travoprost. Although WO2011008756 mentions that the ring-closingreaction would obtain an olefin with a configuration of “cis” at C5˜C6,upon a study made by the inventor, the ring-closing reaction ofWO2011008756 is still involved the generation of a certain amount of5,6-trans isomer.

Latanoprost, Isoproyl unoprostone, Travoprost and Tafluprost all are notsolids, and their free acid forms are not solids, either. Even in allthe processes shown in Schemes A to C, none of the intermediates withthe necessary chiro centers and olefins being established could becrystallized. Consequently, it is unlikely to purify these Prostaglandinanalogues or intermediates by crystallization to remove the isomers.Therefore, it was almost impossible to obtain any isomer freeProstaglandin ester analogues of Formula I-2 in an oil form throughcommon purification technology.

While WO02096898 and WO2011005505 disclose methods for removing the5,6-trans isomer and 15-isomer of latanoprost by preparative HPLC andWO201109599 discloses removing the isomer of latanoprost acid by reversephase preparative HPLC, these purification methods by utilizationpreparative HPLC to remove the isomer are costly and not suitable formass productions.

Given the above, commercially available Prostaglandin ester analogues ofFormula I-2, either as active pharmaceutical ingredients or in the formof formulation products contain a certain amount of isomers,particularly 5,6-trans isomer. For medicine safety and reducingproduction cost, the present invention provides a simpler process forproducing isomer free Prostaglandin ester analogues of Formula I-2 whereunwanted isomers, particularly 5,6-trans isomers can be effectively andeasily removed during the processes.

SUMMARY OF THE INVENTION

In one aspect, the present invention provides novel processes for thepreparation of a compound of Formula I-2 substantially free of the5,6-trans isomer:

wherein

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl; and R₄ is C₁₋₇-alkyl.

In another aspect, the present invention provides novel processes forthe preparation of a compound of Formula IV substantially free of the5,6-trans isomer:

wherein

or a protective group of the carbonyl group; P₁ is a protective groupfor the hydroxyl group;

is a single or double bond; X is OH, OR₄, NHR₅ or NR₄R₅ where R₄ isC₁₋₇-alkyl and R₅ is H or C₁₋₇-alkyl; R₂ is a single bond or aC₁₋₄-alkylene or —CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or anaralkyl, each of which is unsubstituted or substituted by a C₁₋₄-alkyl.

In another aspect, the present invention provides novel processes forthe preparation of a compound of Formula III substantially free of the5,6-trans isomer:

wherein

or a protective group of the carbonyl group; P₁ is a protective groupfor the hydroxyl group;

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl.

In one another aspect, the present invention provides novel processesfor the preparation of high purity prostaglandin or prostaglandinanalogues.

In yet one another aspect, the present invention provides novel isomerfree intermediates useful for the production of high purityprostaglandin or prostaglandin analogues and novel isomer freeprostaglandin analogues.

DETAILED DESCRIPTION OF THE INVENTION Preparation of Compounds ofFormula IV-1

The compound of Formula IV-1

wherein

or a protective group for carbonyl group; P₁ and P₂ are protectivegroups for hydroxyl groups;

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl, can be prepared according to the reactions shown inScheme 1:

As shown in step (a) and step (b) of Scheme 1, the Lactone of FormulaVIII, wherein

or a protective group for carbonyl group; P₁ and P₂ are protectivegroups for hydroxyl groups;

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl, is subjected to a semi-reductive reaction with a suitablereducing agent, such as diisobutyl aluminium hydride (DIBAL), followedby a Wittig reaction to produce a compound of Formula IV-1. Owing to theuse of different solvents, reagents, temperatures, and the like, theresultant cis-selectivity on the C5-C6 double bond of the compound ofFormula IV-1 would depend on the solvents, reagents, temperatures,and/or the other reaction conditions involved in the Wittig reaction.Nevertheless, no matter what the reaction conditions were, it wasinevitable that about 2-10% 5,6-trans isomer would be produced and suchisomer was the main by-product of the preparation according to Scheme 1for the compound of Formula IV-1. Moreover, the Lactone of Formula VIIIwherein

may contain a trace amount of 15β-isomer, and as a result, the15β-isomer of the compound of Formula IV-1 prepared according to Scheme1 would be produced. Most of the lactones of Formula VII were producedfrom the popular, commercially available Corey lactones. Commerciallyavailable Corey lactones contain a trace amount of an enantiomer, andthe lactones of Formula VIII prepared from such Corey lactones maycontain a trace amount of an enantiomer. Consequently, when a compoundof Formula IV-1 was produced according to Scheme 1, an accompanyingenantiomer of the compound of Formula IV-1 would also be produced.

In Scheme 1, suitable protective group for hydroxyl groups, i.e., for P₁and P₂, include, but are not limited to, methoxymethyl,methoxythiomethyl, tert-butylthiomethyl, benzyloxymethyl,2-methoxyethoxymethyl, bis(2-chloroethoxy)methyl, tetrahydropyranyl,tetrahydrothiopyranyl, 4-methoxytetrahydropyranyl,4-methoxytetrahydrothiopyranyl, tetrahydrofuranyl,tetrahydrothiofuranyl, 1-ethoxyethyl, 1-methyl-1-methoxyethyl,triphenylmethyl, allyl, benzyl and substituted benzyl. Preferably, theprotective group is methoxymethyl, methoxythiomethyl,tert-butylthiomethyl, benzyloxymethyl, 2-methoxyethoxymethyl,bis(2-chloroethoxy)methyl, tetrahydropyranyl, tetrahydrothiopyranyl,4-methoxytetrahydropyranyl, 4-methoxytetrahydrothiopyranyl,tetrahydrofuranyl, tetrahydrothiofuranyl, I-ethoxyethyl,1-methyl-1-methoxyethyl, or triphenylmethyl.

In Scheme 1, the suitable protective groups for carbonyl groups

include, but are not limited to, dialkyl ketal, diaralkyl ketal,diacetyl ketal, dithio ketal, 1,3-dioxane, 1,3-dioxolane, 1,3-dithiane,1,3-dithiolane, and 1,3-oxathiolane. Preferred protective groups forcarbonyl groups include dialkyl ketal, 1,3-dioxane, and 1,3-dioxolane.

As an alternative, the compound of Formula IV-1 can be preparedaccording to the reactions shown in Scheme 2:

As shown in step (a) of Scheme 2, the compounds of Formula V-2, wherein

or a protective group for carbonyl group; P₁ and P₂ are protectivegroups for hydroxyl groups;

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl; and R₆ isC₁₋₇-alkyl, each of which is unsubstituted or substituted by aC₁₋₄-alkyl, a halogen or a trihalomethyl, are prepared by a couplingreaction, which is preferably performed at a temperature ranging from−100° C. to 40° C., with an enantiomerically enriched ω-side chain unitof a cuprate derived from the compound of Formula IX-1, Formula IX-2 orFormula IX-3

wherein

or a protective group for carbonyl group; P₂ is a protective group forhydroxyl group; Y is halogen;

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl; R₇ is C₁₋₇-alkyl, of an optically active cyclopentenoneof Formula VI wherein R₆ is C₁₋₇-alkyl; and P₁ is a protective group forhydroxyl group.

Step (b) of Scheme 2 pertains to a keto reduction which was performedwith a reducing agent selected from sodium bis(2-methoxyethoxy)aluminumhydride, diisobutylaluminum hydride, lithiumtri-tert-butoxyaluminohydride, a lithium tri-alkyl borohydride, apotassium tri-alkyl borohydride or a sodium tri-alkyl borohydride or amixture thereof. Preferably, the reducing agent is lithiumtri-sec-butylborohydride (L-selectride), lithium tri-amylborohydride,sodium tri-sec-butylborohydride, potassium tri-sec-butylborohydride, orpotassium tri-amylborohydride or a mixture thereof. More preferably, thereducing agent is lithium tri-sec-butylborohydride.

Step (c) of Scheme 2 pertains to an enzymatic hydrolysis reaction whichwas conducted in the presence of an enzyme, preferably a Candidaantarctica lipase, such as Lipase 435, in an aqueous phase (water or abuffer), and/or an organic solvent such as hexane, toluene,tetrahydrofuran, or methylisobutylketone, or a mixture thereof.

Step (d) of Scheme 2 pertains to an enzymatic or chemical hydrolysisreaction, preferably a chemical hydrolysis reaction. For example, acompound of Formula IV-3 was dissolved in an alcohol, such as methanolor ethanol, and reacted with a base, such as potassium hydroxide orlithium hydroxide to produce a compound of Formula IV-1.

The compounds of Formula IV-1 produced according to Scheme 2 would beaccompanied not only with the by-products (8-isomer and 12-isomer) ofthe conjugate addition reaction of step (a), but the by-product(9-isomer) of the 9-keto reduction reaction of step (b), and even theresultant isomers (5,6-trans isomer and 15β-isomer) produced from theimpurities in the starting material.

In Scheme 2, suitable protective groups for hydroxyl groups (i.e., P₁and P₂) include, but are not limited to, methoxymethyl,methoxythiomethyl, 2-methoxyethoxymethyl, bis(2-chloroethoxy)methyl,tetrahydropyranyl, tetrahydrothiopyranyl, 4-methoxytetrahydropyranyl,4-methoxytetrahydrothiopyranyl, tetrahydrofuranyl,tetrahydrothiofuranyl, 1-ethoxyethyl, 1-methyl-1-methoxyethyl,triphenylmethyl, allyl, benzyl, substituted benzyl and SiR_(a)R_(b)R_(c)wherein R_(a), R_(b) and R_(c) are each independently a C₁₋₈ alkyl,phenyl, benzyl, a substituted phenyl, or a substituted benzyl.Preferably, the protective group is trimethylsilyl, triethylsilyl,tert-butyldimethylsilyl, n-octyldimethylsilyl, methoxymethyl,tetrahydrofuranyl, or tetrahydropyranyl.

In Scheme 2, suitable protective groups for carbonyl group

include, but are not limited to, dialkyl ketal, diaralkyl ketal,diacetyl ketal, dithio ketal, 1,3-dioxane, 1,3-dioxolane, 1,3-dithiane,1,3-dithiolane, and 1,3-oxathiolane. Preferred protective groups forcarbonyl groups include dialkyl ketal, 1,3-dioxane, and 1,3-dioxolane.

Synthesis of Prostaglandin Analogues of Formula I-2 Substantially Freeof the 5,6-Trans Isomer

When used herein, the term “substantially free of the 5,6-trans isomer”or “substantially isomers free” means that a compound in question doesnot contain more than 0.5% of 5,6-trans isomer or does not contain morethan 0.5% of 5,6-trans isomer and, if present, the 15β-isomer.

According to the present invention, a novel approach for the synthesisof a prostaglandin analogue of Formula I-2 substantially free of the5,6-trans isomer:

wherein

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of which isunsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl; and R₄ is C₁₋₇-alkyl, is depicted in Scheme 3.

As shown in Step (a) of Scheme 3, a compound of Formula III wherein

or a protective group for carbonyl group; P₁ and P₂ are protectivegroups for hydroxyl groups; and

, R₂ and R₃ are as defined above for Formula I-2, is prepared by themacrolactonization of a compound of Formula IV-1 wherein

or a protective group for carbonyl group; Pt and P₂ are protectivegroups for hydroxyl groups; and

, R₂ and R₃ are as defined above, which contains 0˜5% 5,6-trans isomeror/and other isomers, and can be prepared from the method of Scheme 1 orScheme 2.

The macrolactonization may involve the activation of the carboxyl or/andhydroxyl functional groups. In this route, the macrolactonizationcomprises the initial formation of a thioester with a suitable reagent,which includes, but is not limited to, S-pyridin-2-ylchloromethanethioate, 2,2′-dipyridyl disulfide/triphenylphosphine, or4-tert-butyl-2-(2-(4-tert-butyl-1-isopropyl-1H-imidazol-2-yl)disulfanyl)-1-isopropyl-1H-imidazole/triphenylphosphine.Optionally, a catalytic amount of an amine, such as triethylamine, canbe added to the reaction, and in addition, a metal ion, such as Ag⁺,Hg²⁺, or Cu²⁺, can also be added to promote the cyclization rate.Suitable sources for providing the metal ion include AgClO₄, AgBF₄,AgOTf, CuBr₂, CuCl₂, and (CF₃CO₂)₂Hg.

The macrolactonization may alternatively involve the initial formationof a mixed anhydride with a suitable reagent in the presence or absenceof a base or a Lewis acid. Suitable reagents for forming the mixedanhydrides include, but are not limited to, 2,4,6-trichlorobenzoylchloride, 2-nitro-6-nitrobenzoic anhydride, p-nitrofluoromethylbenzoicanhydride, p-nitrobenzoic anhydride and the like. Examples of thesuitable bases include 4-(dimethylamino)pyridine, pyrolidinopyridine,triethylamine, N,N-diisopropylethylamine, and isopropyldiethylamine.Examples of suitable Lewis acids include Sc(OTf)₃, TiCl₄, AgClO₄,trimethylsilyl chloride (TMSCl) and TiCl₂(OTf).

The macrolactonization can also be achieved by using a condensationreagent and a base in an appropriate solvent. Suitable condensationreagents include, but are not limited to, N,N′-dicyclohexylcarbodiimide,2-chloro-1-methyl-pyridium iodide,2-chloro-4,5-dihydro-1,3-dimethyl-1H-imidazolium chloride,N,N-diphenylchlorophenylmethyleniminium chloride, cyanuric chloride,1,3-dimethyl-2-chloroimidazolium chloride andN,N,N,N-tetramethylchloroformamidinium chloride, and the like. Examplesof suitable bases include pyridine, triethylamine,diisopropylethylamine, 4-dimethylaminopyridine (DMAP), and the like.Suitable solvents for the condensation reaction include methylenechloride, tetrahydrofuran, and 1,2-dichloroethane, and a mixturethereof.

Upon analyzing a resultant compound of Formula III by HPLC or UPLC, itis unexpectedly found that the resultant compound of Formula III issubstantially free of the 5,6-trans isomer, which reveals that themacrolactonization reaction exhibits a high cis-selectivity, that is,the 5,6-cis compounds of Formula IV-1 dominate in the macrolactonizationreaction whereas the 5,6-trans compounds of Formula IV-1 hardly undergothe macrolactonization reaction.

Step (b) of Scheme 3 involves a deprotection reaction by removing the P₁or/and the P₂ at the ω-side chain. The conditions for carrying out suchdeprotection reactions are obvious to persons skilled in the art. Forexample, the macrolactone of Formula III when P₁ and, if present, P₂ aretetrahydropyranyl protective groups is dissolved in a suitable solvent,such as methanol or a solvent mixture of acetone and water in avolumetric ratio of 5 to 1, treated with a deprotecting agent such ashydrogen chloride, p-toluenesulfonic acid, or pyridiump-toluenesulfonate, and stirred at room temperature for 10 minutes to 10hours. The reaction is quenched with a base, e.g., ammonium hydroxide orthe like, and subjected to a work-up procedure conducted in aconventional manner. It is unexpectedly found that the resultantdeprotected compound of formula II substantially free of the 5,6-transisomer exhibits excellent crystallizability, for example, as evidencedfrom the working examples provided thereinafter as having a meltingpoint higher than 100° C., compared to Compounds IIa, IIb, and IIedisclosed in WO2011008756 (Example 9, 12a-12c) each of which contains acertain amount of a 5,6-trans isomer and is not in a solid form.

The crude product of the compound of Formula II contains a small amountof isomers (such as 15β-isomer, an enantiomer) derived from the impurityin the starting compound of Formula IV-1, and such isomer can be furtherremoved by purifying the crude product via crystallization.

Step (c) in combination with Step (e), and alternatively Step (d) ofScheme 3 involve transesterification reactions of the macrolactone ofFormula II to form a prostaglandin analogue of Formula I-2. In Step (d),the transesterification includes the direct reaction of a compound ofFormula II with a nucleophile selected from the group consisting of aC₁₋₇ alkanol, a C₁₋₇ alkoxide, a C₁₋₇ alkoxide salt, or a mixturethereof to form a prostaglandin analogue of Formula I-2 containing ahydroxyl group and an ester group. According to an embodiment of thepresent invention, the nucleophile is selected from 2-propanol, sodium2-propoxide, or a mixture thereof.

In Step (c) and Step (e), the transesterification includes hydrolyzingthe macrolactone of Formula II to form a compound of Formula I-1containing a hydroxyl group and a carboxyl group, and thenesterificating the compound of Formula I-1 to obtain a prostaglandinanalogue of Formula I-2.

According to the present invention, the resultant compound of FormulaI-2 can be further purified by silylating all the hydroxyl groups in thecompound of Formula I-2 with a silylating agent of formulaXSiR_(a)R_(b)R_(c) wherein X is a halogen, such as F, Cl, or Br, R_(a),R_(b) and R_(c) are each independently a C₁₋₈ alkyl, phenyl, benzyl, asubstituted phenyl, or a substituted benzyl, in a suitable solvent, suchas tetrahydrofuran (THF), dimethylformamide (DMF), or ethyl acetate, andin the presence of a base such as imidazole or triethylamine to form acompound of Formula I-2″,

wherein

R_(a), R_(b) and R_(c) are each independently a C₁₋₈ alkyl, phenyl,benzyl, a substituted phenyl, or a substituted benzyl; and

R₂ and R₃ are as defined above; removing the impurities; and thendesilylating the resultant compound to form a compound of Formula I-2having an improved purity. According to an embodiment of the presentinvention, the silylating agent suitable for the purification reactionis selected from the group consisting of chlorotrimethylsilane,chlorotriethylsilane, chlorodimethyl(octyl)silane, andtert-butylchlorodimethylsilane. As for the conditions for carrying outthe desilylation reaction, they can be those obvious to persons skilledin the art for the deprotection reaction described hereinbefore.

According to some preferred embodiments of the present invention,certain conventionally known prostaglandin analogues substantially freeof isomers can be prepared in the following manners:

Synthesis of Isomers Free Travoprost

As shown in the following Scheme, isomers free Travoprost can be easilyproduced from commercially available compound Xa, without the need ofutilizing chromatography for separating the isomers.

The reaction in step (a) of Scheme 4 is a protection reaction. Examplesof suitable protective groups are described by T. W. Greene in“Protective Groups in Organic Synthesis,” John Wiley & Sons, Inc., 1981.Preferred protective groups are base stable, and may include, but arenot limited to, methoxymethyl, methoxythiomethyl, 2-methoxyethoxymethyl,bis(2-chloroethoxy)methyl, tetrahydropyranyl, tetrahydrothiopyranyl,4-methoxytetrahydropyranyl, 4-methoxytetrahydrothiopyranyl,tetrahydrofuranyl, tetrahydrothiofuranyl, 1-ethoxyethyl,1-methyl-1-methoxyethyl, triphenylmethyl, allyl, and benzyl andsubstituted benzyl. The reaction conditions for conducting theprotection can be those conventionally known in the art. For example,the Lactone of Formula Xa is dissolved in methylene chloride andp-toluenesulfonic acid in a catalytic amount is added thereto. Thereaction mixture is subjected to an ice bath, and an appropriate amountof 3,4-dihydro-2H-pyran is added, and then is stirred at roomtemperature for about 10 minutes to about 10 hours to obtain a protectedLactone of Formula VIIIa.

In Step (b) of Scheme 4, the Lactone of Formula VIIIa is subjected to asemi-reductive reaction with diisobutyl aluminium hydride (DIBAL) toobtain the Lactol of Formula VIIa. The reaction can be conducted at atemperature ranging from −60° C. to −100° C., preferably from −60° C. to−80° C.

In Step (c) of Scheme 4, the Lactol of Formula VIIa is then subjected toa Wittig reaction with the ylide generated from(4-carboxybutyl)triphenylphosphonium bromide and potassiumtert-butoxide, to produce a compound of Formula IV-1a containing 2˜4%5,6-trans isomer.

Step (d) of Scheme 4 is a macrolactonization reaction. No matter whetherthe macrolactonization undergoes through the formation of a thioester ora mixed anhydride or condensation with 1,3-dicyclohexylcarbodiimide, thecompound of IIIa can be obtained.

Upon analysis of a resultant compound of Formula IIIa by UPLC, it isfound that no matter what reagents and reaction conditions were used,all the obtained compounds of Formula IIIa contain the 5,6-trans isomerin an amount less than 0.03% or even less than the amount that can bedetected by UPLC.

Step (e) of Scheme 4 is a deprotection reaction. The macrolactone ofFormula IIIa wherein each of P₁ and P₂ is a tetrahydropyranyl protectivegroup is dissolved in a suitable solvent, such as methanol, treated witha deprotecting agent such as hydrogen chloride, p-toluenesulfonic acid,or pyridium p-toluenesulfonate, and stirred at room temperature for 10minutes to 10 hours. The reaction is quenched with a base, e.g., aqueoussodium bicarbonate solution or the like, and subjected to a work-upprocedure conducted in a conventional manner to obtain the compound ofFormula IIa as a solid. After crystallization, the resultant crystallinecompound and the filtrate of the crystallization were analyzed by UPLC.It was found that either the isomers or the impurities resulting fromthe reactions could be effectively removed by the crystallizationprocess.

The compound of Formula IIa substantially free of isomers and impuritieswas subjected to hydrolysis reaction in step (f) of Scheme 4 to obtainisomers free Travoprost acid ((+)-fluprostenol), which was thensubjected to an esterification reaction in step (g) of Scheme 4 toobtain isomers free Travoprost.

Synthesis of Isomers Free Latanoprost

As shown in Scheme 5, isomers free latanoprost can be produced fromcommercially available compound Xb in the same manner as shown in Scheme4. The product of Formula IIb obtained in step (e) also exhibitsexcellent crystallinity. Analysis of the crude compound of Formula IIbbefore crystallization revealed that the amount of 5,6-trans isomer wasalready less than 0.1%, which showed that the 5,6-trans isomerside-product of the Wittig reaction was removed during themacrolactonization process. Similarly, during the crystallization of thecompound of Formula IIb, the trace amount of the 5,6-trans isomer and ifany, the 15β-isomer derived from the starting compound Xb, and even theimpurities generated from the preceding reactions could be easilyremoved. Consequently, highly pure, isomers free Latanoprost could beeasily obtained.

Synthesis of Pure Tafluprost

As shown in Scheme 6, similar to the reactions shown in Schemes 4 and 5,step(a) is a DIBAL reduction reaction, step(b) is a Wittig reaction,step(c) is a microlactonization reaction, and step(d) is a deprotectionreaction. The compound of Formula IIc obtained in step (d) issubstantially free of the 5,6-trans isomer. It was subjected to thehydrolysis reaction of step (f) and the esterification reaction of step(i) to obtain Tafluprost substantially free of the 5,6-trans isomer. Asan alternative, the compound of Formula IIc could be acylated with anacylating agent of Formula R₈COCl or (R₈CO)₂O wherein R₈ is C₁₋₇-alkyl,unsubstituted phenyl or substituted phenyl such as acetyl chloride,acetic anhydride, benzoyl chloride, benzoic anhydride, or 4-phenylbenzoyl chloride, into the compound of Formula IIc′ wherein R₈ isC₁₋₇-alkyl, unsubstituted phenyl or substituted phenyl which has bettercrystallinity and the compound of Formula IIc′ could be purified bycrystallization so as to remove the trace amount of the isomer, and ifpresent, even the enantiomer to obtain isomer free Tafluprost. Step (g)is a hydrolysis reaction which simultaneously opens the macrolactonering and deacylates the compound to form isomer free Tafluprost acid. InStep (h), the transesterification includes the direct reaction of acompound of Formula IIc with a nucleophile selected from 2-propanol,sodium 2-propoxide, or a mixture thereof to form Tafluprost.

Synthesis of Pure Isopropyl Unoprostone

As shown in Scheme 7, similarly, step(a) is a DIBAL reduction reaction,step(b) is a Wittig reaction, step(c) is a microlactonization reaction,step(e) is a deprotection reaction, step (f) is a hydrolysis reaction,and step (g) is an esterification reaction. For the synthesis ofIsopropyl Unoprostone, the starting compound of Formula VIIId, wherein

P₁ and P₂ are protective groups for the hydroxyl groups, was subjectedto step(a)˜step(c) to form the macrolactone of Formula IIId. Thereafter,the macrolactone of Formula IIId was preferably subjected to step (d)for selectively removing P₂ and oxidizing the resultant hydroxy groupinto a keto group. For example, the macrolactone of Formula IIId,wherein

P₁ is tetrahydropyranyl; and P₂ is tert-butyldimethylsilyl, was reactedin a suitable solvent, such as THF, with tetra-n-butylammonium fluoride(TBAF), so as to selectively remove tert-butyldimethylsilyl; and thenoxidized at proper oxidation conditions, such as Collins oxidation,Swern oxidation, PCC oxidation, PDC oxidation, or TEMPO oxidation,preferably TEMPO oxidation, to form a compound of Formula IIId′substantially free of the 5,6-trans isomer.

The compound of Formula IIId′ was then subjected to the deprotectionreaction in step(e) to remove P₁ so as to form the novel crystallinecompound of Formula IId′, followed by the ring-opening hydrolysisreaction in step (f) to obtain isomer free Unoprostone, which wasfurther subjected to the esterification reaction of step (g) to obtainisomer free isopropyl Unoprostone.

As mentioned above, the macrolactone of Formula IIId could be subjectedto step (d) for removing the protection group for carbonyl to form acompound of Formula IIId′. Alternatively, the macrolactone of FormulaIId could be first subjected to step (e) for removing the protectiongroup P₁, followed by the ring-opening hydrolysis reaction of step (f)and the esterification reaction of step (g), and then subjected to step(h) to remove the protection group for carbonyl, so as also to obtainisopropyl Unoprostone. Alternatively, compound of Formula IId and I-2d″subjected to step (h) to remove the protection group for carbonyl toobtain compound of Formula IId′ and Unoprostone

Synthesis of Prostaglandin Analogues of Formula IV

According to the present invention, a novel approach for the synthesisof a prostaglandin analogue of Formula IV substantially free of the5,6-trans isomer:

wherein

or a protective group for carbonyl group; P₁ and P₂ are protectivegroups for hydroxyl groups;

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl; X is OH, OR, or NR₄R₅ wherein R₄ and R₆ are C₁₋₇-alkyl,and R₅ is H or C₁₋₇-alkyl is depicted in Scheme 8:

Step (a) illustrated in Scheme 8 is macrolactonization reaction of thecompound of Formula IV-1 which contains 1˜10% 5,6-trans isomer and step(b) is related to an amidation reaction. The macrolactone of Formula IIIis reacted with an alkyl amine of Formula HNR₄R₅ where R₄ is C₁₋₇-alkyland R₅ is H or C₁₋₇-alkyl, such as, but not limited to, ethylamine, inan aprotic solvent, such as, but not limited to, tetrahydrofuran, toform a compound of Formula IV-2, wherein X is NR₄R₅, substantially freeof the 5,6-trans isomer. Step (b) is also related to atransesterification reaction. The macrolactone of Formula III is reactedwith a nucleophile selected from the group consisting of a C₁₋₇ alkanol,a C₁₋₇ alkoxide, a C₁₋₇ alkoxide salt, or a mixture thereof to form acompound of Formula IV-3 wherein X is OR₆ substantially free of the5,6-trans isomer. Step (b) is also related to a hydrolysis reaction. Themacrolactone of Formula III is hydrolyzed to form a compound of FormulaIV-1 wherein X is OH, substantially free of the 5,6-trans isomer

Synthesis of Bimatoprost

According to the present invention, isomers free Bimatoprost can besynthesized as shown in Scheme 9:

As shown in Scheme 9, isomers free Bimatoprost can be easily producedfrom commercially available compound Xe. Commercially available compoundXe is subjected to a protection reaction in step (a), reduction withDIBAL in step (b), Wittig reaction in step (c), and macrolactonizationreaction in step (d) to obtain a protected macrolactone of Formula IIIesubstantially free of the 5,6-trans isomer. Step (e) of Scheme 9represents an amidation reaction of the protected macrolactone ofFormula IIIe to form a protected Bimatoprost in a high yield, and thenthe protected Bimatoprost is subjected to the deprotection reaction ofstep (f) to obtain crude Bimatoprost substantially free of the 5,6-transisomer. Isomers free Bimatoprost can be obtained by one-timecrystallization of the crude Bimatoprost. As compared to the prior artprocesses where Wittig reaction product of Formula IV-1e containing 2˜3%5,6-trans isomer was subjected to esterification and amidation to obtaincrude Bimatoprost which still contained 2˜3% 5,6-trans isomer andrequires recrystallization many times to obtain isomers free Bimatoprostin a significantly lower yield, the process according to the presentinvention includes a macrolactonization reaction in step (d) to allowthe removal of the 5,6-trans isomer produced in the Wittig reaction andthe resultant Bimatoprost upon further purification-by-crystallizationcan be obtained in a higher yield.

Synthesis of Compounds of Formula III

According to another aspect of the present invention, a process for thesynthesis of compounds of Formula III substantially free of the5,6-trans isomer

is provided, wherein

or a protecting group for carbonyl group; P₁ and P₂ are protectinggroups for the hydroxyl groups;

is a single or double bond; R₂ is a single bond or a C₁₋₄-alkylene or—CH₂O—; and R₃ is a C₁₋₇-alkyl or an aryl or an aralkyl, each of whichis unsubstituted or substituted by a C₁₋₄-alkyl, a halogen or atrihalomethyl, by macrolactonizing a compound of Formula IV-1 obtainedeither from Scheme 1 or from Scheme 2. The macrolactonization can beconducted in a same manner as described hereinbefore.

Novel Compounds of Formula III

The present invention also provides novel compounds selected from thegroup consisting of:

wherein

and P₁ and P₂ are protecting groups for the hydroxyl groups, which areindependently selected from the group consisting of methoxymethyl,methoxythiomethyl, tert-butylthiomethyl, benzyloxymethyl,2-methoxyethoxymethyl, bis(2-chloroethoxy)methyl, tetrahydropyranyl,tetrahydrothiopyranyl, 4-methoxytetrahydropyranyl,4-methoxytetrahydrothiopyranyl, tetrahydrofuranyl,tetrahydrothiofuranyl, 1-ethoxyethyl, 1-methyl-1-methoxyethyl,triphenylmethyl.

Novel Isomer Free Compounds of Formula II

Given the above, the invention further provides crystalline compoundssubstantially free of the 5,6-trans isomer and 15β-isomer selected fromthe group consisting of compound IIa, IIb, IIc, IId, and IIe:

wherein

M is O or a protecting group of the carbonyl group. For the compounds ofFormula IId, the invention provides in particular the compound ofFormula IId′:

Novel Compounds of Formula IIc′

The invention further provides crystalline compound of Formula IIc′substantially free of the 5,6-trans isomer and 15β-isomer

wherein R₈ is C₁₋₇-alkyl, unsubstituted phenyl or substituted phenyl.

Novel Isomers Free Compounds of Formula I-1

According to yet another aspect of the present invention, a compoundsubstantially free of the 5,6-trans isomer selected from the groupconsisting of travoprost free acid, latanoprost free acid, bimatoprostfree acid, tafluprost free acid, fluprostenol, cloprostenol, andunoprostone. Preferably, the compound substantially free of the5,6-trans isomer contains less than 0.1% of the 5,6-trans isomer.

Novel Isomer Free Prostaglandin Analogues of Formula I-2

As mentioned above, the processes according to the present invention areuseful in the production of isomers free prostaglandin analogues.Therefore, the present invention further provides an isomer freeprostaglandin analogue selected from the group consisting of Latanoprostcontaining less than 0.2% isomers, Travoprost containing less than lessthan 0.5% isomers and less then 0.1% for each single isomer, Tafluprostcontaining less than 0.5% isomers and less than 0.1% for each singleisomer, and Unoprostone Isopropyl ester containing less than 0.5%isomers and less than 0.1% for each single isomer, among which,preferably, Latanoprost contains less than 0.1% isomers; Travoprostcontains less than 0.2% isomers, Tafluprost contains less than 0.2%isomers, and Unoprostone Isopropyl ester contains less than 0.2%isomers. More preferably, Latanoprost contains less than 0.1% isomers;Travoprost contains less than 0.1% isomers, Tafluprost contains lessthan 0.1% isomers, and Unoprostone Isopropyl ester contains less than0.1% isomers.

The following examples are provided to further illustrate the presentinvention but are not intended to limit the scope thereof. Anymodifications or changes without departing from the spirits of theinvention and obvious to a person of ordinary skill in the art fallwithin the scope of the disclosure in the specification and the appendedclaims.

Examples 1˜12 Preparation of Travoprost and its Intermediates Via WittigReaction Example 1(3aR,4R,5R,6aS)-5-((tetrahydro-2H-pyran-2-yl)oxy)-4-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)hexahydro-2H-cyclopenta[b]furan-2-one

p-Toluenesulfonic acid monohydrate (0.35 g, 1.8 mmol) was added to asolution of(3aR,4R,5R,6aS)-4-((R,E)-4-(3-(trifluoromethyl)phenoxy)-3-hydroxybut-1-enyl)-hexahydro-5-hydroxycyclopenta[b]furan-2-one(15.0 g, 40.3 mmol) and 3,4-dihydro-2H-pyran (8.47 g, 100.7 mmol) in THF(200 mL) at room temperature and the mixture was stirred for 2.5 hr (TLCmonitoring). Saturated aqueous solution of sodium bicarbonate (200 mL)was poured into the reaction mixture and the mixture was stirred for 5minutes. The organic layer was separated and the aqueous layer wasextracted with ethyl acetate (200 mL). The combined organic layers weredried over magnesium sulfate, filtered off solid and concentrated underreduced pressure to give 24.0 g of crude product. The crude product waspurified by column chromatography and then concentrated under reducedpressure to provide 19.0 g of the titled compound (87.5% yield).

¹H-NMR (400 MHz, CDCl₃):δ 7.390 (t, 1H), 7.196 (d, 1H), 7.129 (s, 1H),7.029-7.097 (m, 1H), 5.484-5.727 (m, 2H), 4.923-5.002 (m, 1H),4.645-4.709 (m, 2H), 4.443-4.490 (m, 1H), 3.772-4.160 (m, 5H),3.448-3.529 (m, 2H), 2.362-2.805 (m, 4H), 2.078-2.202 (m, 2H),1.452-1.790 (m, 12H).

13C-NMR (100 MHz, CDCl₃):δ 177.175 (176.977, 176.605), 158.890, 134.874,134.676 (132.384), 131.770 (q), 130.008 (129.948), 129.196 (129.006),128.422, 123.917 (q), 118.251 (118.167), 117.609 (q), 111.393 (q),98.713 (98.448, 98.394), 95.874 (95.844, 94.964), 83.707 (83.434,83.123, 82.857), 79.616 (79.373), 74.606 (74.553, 73.680, 73.642),70.796 (70.705, 70.644), 62.371 (61.718), 54.735 (54.196), 42.355(42.029, 41.960), 35.903 (35.842), 35.341 (35.068, 34.772, 34.499),30.582 (30.560, 30.476), 30.377, 25.390 (25.375), 19.349 (19.288,19.273, 19.220), 18.939 (18.908).

Example 2(3aR,4R,5R,6aS)-5-((tetrahydro-2H-pyran-2-yl)oxy)-4-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)hexahydro-2H-cyclopenta[b]furan-2-ol

(3aR,4R,5R,6aS)-5-((tetrahydro-2H-pyran-2-yl)oxy)-4-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)hexahydro-2H-cyclopenta[b]furan-2-one(19.0 g, 35.3 mmol) was dissolved in toluene (200 mL), followed bycooling to −70° C., and DIBAL (1.0M in hexane, 53 mL, 53 mmol) was addeddropwisely. Then the reaction was quenched by adding saturated aqueoussolution of ammonium chloride (10 mL) at −70° C. The resulting mixturewas poured into a 2M sodium bisulfate aqueous solution (200 mL) at roomtemperature and stirring was continued for 30 minutes. After separationof the organic layers, toluene (200 mL) was added to the aqueous layer.The combined organic layers were concentrated under reduced pressure togive 25.0 g of crude titled compound.

¹H-NMR (400 MHz, CDCl₃): δ7.345 (t, 1H), 7.468 (d, 1H), 7.128 (s, 1H),7.020-7.093 (m, 1H), 5.440-5.850 (m, 3H), 4.414-4.920 (m, 5H),3.760-4.025 (m, 4H), 3.416-3.514 (m, 3H), 2.232-2.501 (m, 3H),1.848-2.211 (m, 3H), 1.352-1.804 (m, 12H).

¹³C-NMR (100 MHz, CDCl₃):δ 158.996, 137.098, 136.399 (133.308), 134.418(134.388, 133.636, 133.591), 131.694 (q), 129.932 (129.864), 128.634(128.361, 128.240, 127.966), 127.784 (127.519, 127.420, 127.025),123.940 (q), 118.312 (118.258, 118.160), 117.446 (q), 111.439 (q),99.897 (99.867), 94.683, 83.350 (83.312, 83.039, 82.758), 80.307(79.889, 79.494), 73.916 (73.885, 73.862, 73.824), 71.153 (71.054,70.895, 70.811), 62.318 (61.604, 61.574), 54.780 (54.287, 54.226,54.094), 45.141 (45.080, 44.875, 44.852), 39.152 (39.076, 38.985),38.932 (38.894, 38.727, 38.583), 30.658 (30.620, 30.575, 30.544), 30.491(30.461, 30.385), 25.413 (25.375, 25.345, 25.284), 19.394 (19.349,19.273, 19.159), 19.022 (18.954, 18.916, 18.863).

Example 3(Z)-7-((1R,2R,3R,5S)-5-hydroxy-3-((tetrahydro-2H-pyran-2-yl)oxy)-2-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoicacid

A suspension of (4-carboxybutyl)triphenylphosphonium bromide (62.33 g,140.6 mmol) and potassium tert-butoxide (31.55 g, 281.1 mmol) in THF(500 mL) was cooled to −20° C. for 30 min. And, a solution of(3aR,4R,5R,6aS)-5-((tetrahydro-2H-pyran-2-yl)oxy)-4-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)hexahydro-2H-cyclopenta[b]furan-2-ol(25.0 g crude product from example 2) in THF (50 mL) at −20° C. wasadded and the reaction mixture was stirred for 16 hr. Then saturatedaqueous solution of ammonium chloride (300 mL) was added and theresulting suspension was stirred for 30 min at room temperature. Afterseparation of the organic layers, the aqueous layer was adjusted to havea pH of 6.0 by addition of a 2M sodium bisulfate solution and extractedwith ethyl acetate (300 mL). The combined organic layers were dried overmagnesium sulfate and concentrated under reduced pressure to give 44.0 gof crude titled compound.

¹H-NMR (400 MHz, CDCl₃):δ 7.362 (t, 1H), 7.185 (d, 1H), 7.145 (s, 1H),7.039-7.112 (m, 1H), 5.616-5.822 (m, 2H), 5.419-5.551 (m, 1H),5.300-5.364 (m, 1H), 4.760-4.948 (m, 1H), 4.644-4.662 (m, 1H),4.493-4.581 (m, 1H), 3.772-4.162 (m, 5H), 3.423-3.538 (m, 2H),2.403-2.583 (m, 1H), 1.974-2.315 (m, 7H), 1.410-1.957 (m, 17H).

¹³C-NMR (100 MHz, CDCl₃):δ 177.797 (177.577), 158.996, 137.879(137.538), 134.950 (134.562), 131.785 (q), 129.963 (129.887), 129.553(129.447, 129.249, 129.113), 128.073 (127.997, 127.094, 127.048),125.410 (q), 118.213 (118.099), 117.526 (q), 111.496 (q), 98.675(98.546, 98.144, 97.939), 96.375 (96.337, 94.501, 94.410), 82.014(81.916, 80.959, 80.610), 75.160 (74.948, 73.893, 73.870), 73.399(73.202, 73.035, 72.807), 71.213 (71.084, 70.879, 70.819), 62.735(62.621, 62.522, 62.447), 61.763 (61.695, 61.596, 61.498), 53.369(53.110, 52.905, 52.807), 50.666 (50.552, 50.416), 41.452 (41.383,39.645, 39.539), 33.117 (32.950), 30.924, 30.651 (30.620, 30.582,30.552), 30.324, 26.385 (26.271), 25.724 (25.687, 25.656, 25.633),25.406 (25.353), 24.487 (24.427), 19.607 (19.531, 19.341, 19.273),18.992 (18.946, 18.810, 18.779).

Determination of Isomer Content of the Product:

A sample of the product was esterified using K₂CO₃ and 2-iodopropane inDMF. After 4 h at 60° C., water and ethyl acetate were added and theresultant solution was extracted with ethyl acetate. Afterdrying-concentration of the extracts, a crude 11,15-protected travoprostwas obtained. The crude 11,15-protected travoprost was deprotected using3N HCl in THF and water. After 1 h at 25° C., saturated aqueous solutionof sodium bicarbonate was added and the solution was extracted withethyl acetate. After drying-concentration of the extracts, a crudetravprost was obtained. UPLC (ACQUITY UPLC HSS C18) analysis showed thatthe crude product contains 2.8% 5,6-trans isomer.

Examples 4˜7 Preparation of Protected Travoprost 1,9-Lactone from WittigReaction Product(8aR,9R,10R,1aS,Z)-10-((tetrahydro-2H-pyran-2-yl)oxy)-9-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

¹H-NMR (400 MHz, CDCl₃):δ 7.369 (t, 1H), 7.196 (d, 1H), 7.151 (s, 1H),7.043-7.116 (m, 1H), 5.543-5.790 (m, 2H), 5.316-5.362 (m, 1H), 5.195 (m,2H), 4.653-4.944 (m, 2H), 4.524-4.553 (m, 1H), 3.963-4.068 (m, 2H),3.785-3.935 (m, 3H), 3.446-3.508 (m, 2H), 2.103-2.627 (m, 7H),1.505-1.898 (m, 17H).

¹³C-NMR (100 MHz, CDCl₃):δ 173.600 (173.554, 173.509, 173.455), 159.064(159.034, 158.958, 158.927), 136.612 (136.475), 133.857 (133.667),131.822 (q), 131.633 (131.375), 130.069, 129.948 (129.887), 129.158(129.059), 127.420 (127.291), 123.917 (q), 118.289 (118.152), 117.526(q), 111.420 (q), 99.427 (99.396, 99.146, 98.098), 95.844 (95.814,94.842, 94.804), 81.703 (81.476, 78.295, 78.075), 74.766 (74.470),73.946 (73.900), 71.304 (71.130, 70.948, 70.849), 62.538 (62.409,62.052), 61.824 (61.642, 61.407), 44.898 (44.822, 44.791, 44.632),39.531, 37.619, 36.047, 30.734 (30.689, 30.643), 30.529 (30.476), 26.711(26.453), 25.489 (25.451, 25.413, 25.375), 19.591 (19.516), 19.068(19.007), 18.810 (18.787).

Example 4

A solution of(Z)-7-((1R,2R,3R,5S)-5-hydroxy-3-((tetrahydro-2H-pyran-2-yl)oxy)-2-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoic acid (22.0 g crude product from Example 3) inTHF (125 mL) was treated with 2,2′-dipyridyl disulfide (8.39 g, 38.1mmol) and triphenylphosphine (6.25 g, 23.9 mmol). This mixture was thenstirred for 2 hr. at room temperature under an atmosphere of nitrogen.The resulting mixture was heated to 80° C. for 18 hr (TLC monitoring)followed by removal of THF under reduced pressure, and the residue wasdiluted with saturated aqueous solution of sodium bicarbonate (100 mL)and extracted with ethyl acetate (100 mL). The organic layer was driedover magnesium sulfate and concentrated under reduced pressure to give25.0 g of a crude title compound. The crude title compound was purifiedby column chromatography to provide 8.0 g of the title compound (75%yield, 3 steps).

Determination of Isomer Content of the Product:

A sample of the product was hydrolyzed using methanol and 3N NaOH. After2 h at 25° C., the mixture was acidified and extracted with ethylacetate. After drying-concentration of the extracts, a crude11,15-protected travoprost acid was obtained. The crude 11,15-protectedtravoprost acid was esterified using K₂CO₃ and 2-iodopropane in DMF.After 2 h at 60° C., water and ethyl acetate were added and theresultant solution was extracted with ethyl acetate. Afterdrying-concentration of the extracts, a crude 11,15-protected travoprostwas obtained. The crude 11,15-protected travoprost was deprotected using3N HCl in THF and water. After 1 h at 25° C., saturated aqueous solutionof sodium bicarbonate was added and the resultant solution was extractedwith ethyl acetate. After drying-concentration of the extracts, a crudetravoprost was obtained. UPLC (ACQUITY UPLC HSS C18) analysis showedthat no 5,6-trans isomer was detectable.

Example 5

To a solution of the(Z)-7-((R,2R,3R,5S)-5-hydroxy-3-((tetrahydro-2H-pyran-2-yl)oxy)-2-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoic acid (5.00 g crude product from Example 3) andN,N-diisopropylethylamine (1.70 g, 13.2 mmol) in methylene chloride (100mL) at room temperature under nitrogen, 2,4,6-trichlorobenzoyl chloride(1.90 g, 7.8 mmol) was added and the resulting mixture was stirred for 1hr at room temperature. The reaction mixture was cooled to −15 to −20°C. and a solution of 4-dimethylaminopyridine (1.66 g, 13.6 mmole) inmethylene chloride (15 mL) was added dropwise over 10 minutes. Thereaction mixture was further stirred for 30 minutes at −15 to −16° C.The reaction mixture was quenched with saturated sodium bicarbonatesolution (100 mL). The organic layer was separated. The aqueous layerwas extracted with methylene chloride (50 mL). The combined organiclayers were dried over magnesium sulfate, filtered and concentratedunder reduced pressure to give 8.0 g of crude title compound. The crudetitle compound was purified by column chromatography providing 2.0 g ofthe title compound. (82.4% yield, 3 steps)

Determination of Isomer Content of the Product:

According to the same method as described in Example 4, UPLC (ACQUITYUPLC HSS C18) analysis of the crude product showed that no 5,6-transisomer was detectable.

Example 6

To a solution of the(Z)-7-((1R,2R,3R,5S)-5-hydroxy-3-((tetrahydro-2H-pyran-2-yl)oxy)-2-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoic acid (3.0 g crude product from Example 3) andN,N-diisopropylethylamine (1.02 g, 7.9 mmole) in methylene chloride (60mL) at room temperature under nitrogen, benzoyl chloride (0.66 g, 4.7mmole) was added and the resulting mixture was stirred for 1 hr at roomtemperature. The reaction mixture was cooled to −15 to −20° C. and asolution of 4-dimethylaminopyridine (0.97 g, 7.9 mmole) in methylenechloride (10 mL) was added dropwise over 10 minutes. The reactionmixture was further stirred for 30 minutes at −15 to −16° C. Thereaction mixture was quenched with saturated sodium bicarbonate solution(60 mL). The organic layer was separated. The aqueous layer wasextracted with methylene chloride (50 mL). The combined organic layerswere dried over magnesium sulfate, filtered and concentrated underreduced pressure to give 5.0 g of crude title compound. The crude titlecompound was purified by column chromatography providing 1.17 g of thetitle compound. (80.3% yield, 3 steps)

Determination of Isomer Content of the Product:

According to the same method as described in Example 4, UPLC (ACQUITYUPLC HSS C18) ananlysis of the crude product showed that no 5,6-transisomer was detectable.

Example 7

To a solution of the(Z)-7-((1R,2R,3R,5S)-5-hydroxy-3-((tetrahydro-2H-pyran-2-yl)oxy)-2-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1en-1-yl)cyclo pentyl)hept-5-enoic acid (3.0 g, 4.8 mmole) and4-dimethylaminopyridine (0.03 g, 0.25 mmole) in methylene chloride (30mL) under nitrogen. The reaction mixture was cooled to 0° C. and asolution of N,N′-dicyclohexylcarbodiimide (1.98 g 9.6 mmole) inmethylene chloride (20 mL) was added dropwise over 5 minutes. Thereaction mixture was further stirred for 3 hr at room temperature. Thereaction mixture was quenched with saturated sodium bicarbonate solution(20 mL). The organic layer was separated. The aqueous layer wasextracted with methylene chloride (20 mL). The combined organic layerswere dried over magnesium sulfate, filtered and concentrated underreduced pressure to give 5.0 g of crude title compound. The crude titlecompound was purified by column chromatography providing 1.05 g of thetitle compound (72.0% yield, 3 steps) Determination of isomer content ofthe product:

According to the same method as described in Example 4, UPLC (ACQUITYUPLC HSS C18) ananlysis of the crude product showed that no 5,6-transisomer was detectable.

Example 8(8aR,9R,10R,11aS,Z)-10-hydroxy-9-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

p-Toluenesulfonic acid monohydrate (0.20 g, 1.1 mmol) was add to astirred solution of(8aR,9R,10R,11aS,Z)-10-((tetrahydro-2H-pyran-2-yl)oxy)-9-((3R,E)-3-((tetrahydro-2H-pyran-2-yl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[h]oxecin-2(3H)-one(14.0 g, 23.0 mmol) in methanol (150 mL). The mixture was stirred for 2hr at room temperature (TLC monitoring). Then, the reaction mixture wasquenched with saturated sodium bicarbonate aqueous solution (200 mL),and the methanol was removed under reduced pressure. The residue wasextracted with ethyl acetate (200 mL). The organic layer was separated.The aqueous layer was extracted with ethyl acetate (200 mL). Thecombined organic layers were dried over magnesium sulfate, filtered andconcentrated under reduced pressure to give 15.0 g of the crude product.The crude product was subjected to further purification by flash columnchromatography to obtain 8.2 g of the title compound as a solid. DSCanalysis showed that the solid contained two crystalline forms (mp92-97° C. and mp 113-118° C.) The solid was recrystallized from amixture of hexane and ethyl acetate to give 7.3 g of title compound as asingle crystalline form (mp 113˜118° C.). The x-ray powder diffractionpattern of crystalline title compound (mp 115˜120° C.) hascharacteristic peaks expressed in degrees 2θ at approximately 10.7,12.1, 13.4, 14.5, 14.8, 16.0, 16.6, 17.7, 18.4, 18.5, 19.4, 20.5, 21.0,22.0, 22.4, 23.3, 24.6, 24.7, 25.1, 28.9, 29.9, 37.9, 44.1.

¹H-NMR (400 MHz, CDCl₃):δ 7.387 (t, 1H), 7.227 (d, 1H), 7.145 (s, 1H),7.080 (m, 1H), 5.721-5.776 (m, 1H), 5.623-5.683 (m, 1H), 5.309-5.354 (m,1H), 5.222 (m, 2H), 4.527 (m, 1H), 3.947-4.033 (m, 2H), 3.812-3.874 (m,1H), 3.510 (br s, 1H), 3.409 (br s, 1H), 2.561-2.635 (m, 1H),2.098-2.418 (m, 6H), 1.587-1.870 (m, 5H).

¹³C-NMR (100 MHz, CDCl₃):δ 173.471, 158.593, 135.147, 131.937 (q),131.534, 131.147, 130.099, 127.276, 123.856 (q), 118.099, 117.928 (q),111.446 (q), 75.935, 71.897, 70.993, 56.222, 44.981, 40.260, 36.040,26.711, 26.559, 25.269.

Example 9(Z)-7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoicacid (Travoprost acid)

A solution of(8aR,9R,10R,11aS,Z)-10-hydroxy-9-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(3.0 g from Example 8) in 2-propanol (25 mL) was treated with 3Npotassium hydroxide aqueous solution (6.8 mL). This mixture was stirredat 50° C. for 2 hr. The reaction mixture was cooled and further adjustedwith 3N hydrochloric acid aqueous solution to a pH of 8.5±0.2, and mostof the solvent was removed under reduced pressure. The residue wasdiluted with saturated aqueous solution of sodium bicarbonate (20 mL)and ethyl acetate (20 mL). The mixture was stirred at room temperaturefor 5 minutes. The organic phase and the aqueous phase were separatelycollected. The aqueous layer was adjusted to a pH of 3.0±0.2 with 3Nhydrochloric acid aqueous solution at room temperature and extractedwith ethyl acetate (100 mL). The organic layer was dried over magnesiumsulfate and concentrated under reduced pressure to give 3.3 g of crudeTravoprost acid.

Determination of Isomer Content of the Product:

A sample of this product was esterified using K₂CO₃ and 2-iodopropane inDMF. After 4 h at 60° C., water and ethyl acetate were added and thereaction was extracted with ethyl acetate. After drying-concentration ofthe extracts, crude travprost was obtained. UPLC (ACQUITY UPLC HSS C18)ananlysis of the crude product showed that no isomer was detectable.

¹H-NMR (400 MHz, CDCl₃):δ 7.343 (t, 1H), 7.179 (d, 1H), 7.116 (s, 1H),7.055 (d, 1H), 5.631-5.704 (m, 2H), 5.278-5.422 (m, 2H), 4.520-4.527 (m,1H), 3.950-4.008 (m, 2H), 2.034-2.361 (m, 8H), 1.337-1.745 (m, 7H).

¹³C-NMR (100 MHz, CDCl₃):δ 171.411, 158.794, 135.472, 131.877 (q),130.113, 130.010, 129.682, 129.106, 123.960 (q), 118.097, 117.769 (q),111.549 (q), 77.382, 71.751, 71.065, 70.907, 55.292, 49.952, 42.597,31.527, 26.120, 25.094, 24.227.

Example 10 (Z)-isopropyl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoate (Travoprost)

A solution of crude Travoprost acid (1.1 g from Example 9) in DMF (11mL) was treated with K₂CO₃ (0.90 g, 6.5 mmol) and 2-iodopropane (0.74 g,4.4 mmol). This mixture was then stirred at 80° C. for 2 hr under anatmosphere of nitrogen (TLC monitoring). Water (30 mL) and ethyl acetate(30 mL) were added and the mixture was stirred for 10 min. The aqueouslayer was separated and extracted with ethyl acetate (30 mL), and thecombined organic layer was dried over magnesium sulfate and concentratedunder reduced pressure to give 1.0 g of crude Travoprost. The crudeTravoprost was purified by column chromatography and then concentratedunder reduced pressure to provide 0.89 g of Travoprost (78.3% yield, 2steps). UPLC (ACQUITY UPLC HSS C18) ananlysis of the product showed thatno isomer and impurities were detectable.

¹H-NMR (400 MHz, CDCl₃):δ 7.337 (t, 1H), 7.209 (d, 1H), 7.142 (s, 1H),7.084 (d, 1H), 5.647-5.744 (m, 2H), 5.334-5.434 (m, 2H), 4.970 (heptet,1H), 4.518-4.528 (m, 1H), 4.163-4.170 (m, 1H), 3.939-4.020 (m, 3H),3.294 (br s, 1H), 3.262 (br s, 1H), 2.588 (br s, 1H), 2.360-2.410 (m,1H), 2.015-2.305 (m, 7H), 1.760 (dd, 1H), 1.646 (quintet, 2H),1.494-1.554 (m, 1H), 1.201 (d, 6H)

13C-NMR (100 MHz, CDCl₃):δ 173.511, 158.656, 135.420, 131.857 (q),130.015, 129.794, 128.901, 123.857 (q), 118.038, 117.748 (q), 111.466(q), 77.710, 72.649, 71.992, 70.840, 67.672, 55.748, 50.176, 42.824,33.970, 26.565, 25.450, 24.802, 21.771

Example 11 (Z)-isopropyl7-((1R,2R,3R,5S)-3,5-bis((triethylsilyl)oxy)-2-((R,E)-3-((triethylsilyl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoate

A solution of crude Travoprost acid (1.1 g from Example 9) in DMF (11mL) was treated with K₂CO₃ (0.90 g, 6.5 mmol) and 2-iodopropane (0.74 g,4.4 mmol). This mixture was then stirred at 80° C. for 2 hr under anatmosphere of nitrogen (TLC monitoring). Water (30 mL) and ethyl acetate(30 mL) were added and the mixture was stirred for 10 min. The aqueouslayer was separated and extracted with ethyl acetate (30 mL), and thecombined organic layer was dried over magnesium sulfate and concentratedunder reduced pressure to give 1.2 g of crude Travoprost. The crudeTravoprost was dissolved in 10 mL ethyl acetate in 25 mL round-bottomflask, followed by addition of imidazole (0.82 g, 12 mmol) at roomtemperature. Chlorotriethylsiliane (1.6 g, 10.6 mmol) was added intothis flask and stirred for 10 minutes. White solid was produced andfiltered off and washed with 50 mL ethyl actate twice. All organicsolvent was combined and washed with 15 mL saturated NaHCO₃ aqueoussolution twice. The organic layer was dried over anhydrous MgSO₄, solidwas filtered off and solvent was evaporated under vacuum. The crudeproduct was purified by chromatography on silica gel using a mixture ofhexane and ethyl acetate as a gradient eluent. Yield of the titlecompound was 1.85 g. (91.6%)

1H-NMR (400 MHz, CDCl3): δ 7.360 (t, 1H), 7.181 (d, 1H), 7.088 (s, 1H),7.035 (d, 1H), 5.582-5.679 (m, 2H), 5.396-5.458 (m, 1H), 5.266-5.347 (m,1H), 4.985 (heptet, 1H), 4.516-4.554 (m, 1H), 4.114-4.148 (m, 1H),3.813-3.871 (m, 3H), 2.385-2.450 (m, 1H), 2.157-2.276 (m, 4H),2.006-2.087 (m, 3H), 1.577-1.682 (m, 3H), 1.395-1.457 (m, 1H), 1.208 (d,6H), 0.905-0.987 (m, 27H), 0.514-0.666 (m, 18H)

¹³C-NMR (100 MHz, CDCl₃): δ 173.137, 159.026, 133.644, 131.769 (q),130.798, 129.849, 129.811, 128.801, 123.955 (q), 117.985, 117.260 (q),111.059 (q), 76.853, 72.891, 71.540, 71.145, 67.312, 54.484, 49.437,44.928, 34.127, 26.726, 25.034, 24.905, 21.785, 6.878, 6.794, 4.995,4.897, 4.874

Example 12 (Z)-isopropyl7-((R,2R,3R,5S)-3,5-dihydroxy-2-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoate(Travoprost)

The product of Example 11 (0.8 g) was dissolved in 10 ml acetone and 2ml water, followed by addition of 0.1 g p-toluenesulfonic acidmonohydrate. The reaction solution was stirred at room temperature for 1hour and concentrated until two separate layers were observed. 30 mlethyl acetate was added for extraction and phase separation. The organiclayer was washed with saturated sodium bicarbonate solution and brine,dried over anhydrous magnesium sulfate, and subjected to vacuumevaporation for removal of the solvent until dryness. The crudeTravoprost was purified by column chromatography and then concentratedunder reduced pressure to provide 0.44 g of Travoprost. UPLC (ACQUITYUPLC HSS C18) ananlysis of the product showed that no isomer andimpurities were detectable and the purity was higher then 99.9%.

Examples 13˜18 Preparation of Travoprost and its Intermediates ViaConjugate Addition Example 13 (5Z)-isopropyl7-((1R,2R,3R)-2-((R,E)-4-(3-(trifluoromethyl)phenoxy)-3-(triethylsilyloxy)but-1-enyl)-3-triethylsilyloxy-5-oxocyclopentyl)hept-5-enoate

A 500 mL three-necked flask was flame dried and allowed to be cooledunder nitrogen. (R,E)-triethyl ((4-(tributylstannyl)-1-(3-(trifluoromethyl)phenoxy)but-3-en-2-yl)oxy)silane (22.53g, 35.46 mmol) and 200 mL tetrahydrofuran were added to the reactionflask, followed by dropwise addition of n-butyl lithium (22.2 mL, 1.6 Min hexane) at −70° C. A suspension solution of copper cyanide (3.18 g,35.46 mmol) in 30 mL tetrahydrofuran was cooled to −10° C. and followedby dropwise addition of methyl lithium (17.76 mL, 2 M in ether). Thehomogenous organo-metallic solution was cooled and added into thereaction flask while stirring for 30 minutes. Then, a solution of(R,Z)-isopropyl7-(3-triethylsilyloxy-5-oxocyclopent-1-en-1-yl)hept-5-enoate (4.5 g,containing 5% of 5,6-trans isomer) in 15 mL tetrahydrofuran at −70° C.was added to the reaction mixture for 10 minutes. After being stirredfor another 20 minutes, the reaction mixture was poured into a mixtureof 9/1 (v/v) saturated aqueous NH₄Cl/NH₄OH solution to be phaseseparated. The aqueous layer was extracted with ethyl acetate. Theorganic layers were combined and dried over anhydrous MgSO₄. The solidwas filtered off and organic solvent was evaporated off under vacuum.The crude product was purified by chromatography on silica gel using amixture of hexane and ethyl acetate as a gradient eluent. Yield of thetitle compound was 5.10 g (59.3%).

¹H-NMR (400 MHz, CDCl₃): δ 7.346 (t, 1H), 7.167 (d, 1H), 7.068 (s, 1H),7.019 (d, 1H), 5.670-5.782 (m, 2H), 5.264-5.408 (m, 2H), 4.956 (heptet,1H), 4.539-4.546 (m, 1H), 4.033-4.087 (m, 1H), 3.862 (d, 2H),2.491-2.656 (m, 2H), 2.119-2.400 (m, 5H), 1.999-2.049 (m, 3H),1.586-1.655 (m, 2H), 1.182 (d, 6H), 0.894-0.969 (m, 18H), 0.528-0.652(m, 12H),

¹³C-NMR (100 MHz, CDCl₃): δ 214.785, 172.954, 158.882, 132.255, 131.800(q), 131.428, 130.927, 129.910, 126.464, 123.910 (q), 117.985, 117.389(q), 111.930 (q), 72.678, 72.564, 70.864, 67.335, 53.961, 52.837,47.706, 33.968, 26.605, 25.079, 24.723, 21.740, 6.764, 6.680, 4.859,4.752.

Example 14 (5Z)-isopropyl7-((1R,2R,3R,5S)-2-((R,E)-4-(3-(trifluoromethyl)phenoxy)-3-(triethylsilyoxy)but-1-enyl)-5-dihydroxy-3-(triethylsilyloxy)cyclopentyl)hept-5-enoate

A 100 mL three-necked flask was flame dried and allowed to be cooledunder nitrogen. (Z)-isopropyl7-((1R,2R,3R,5S)-3-triethylsilyloxy-2-((R,E)-3-triethylsilyloxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-5-hydroxycyclopentyl)hept-5-enoate(3.6 g, 4.95 mmol) and 50 mL tetrahydrofuran were added to the reactionflask, followed by dropwise addition of L-Selectride (4.95 ml, 1M intetrahydrofuran) at −70° C. Then, the reaction mixture was warmed toroom temperature and quenched by 50 mL saturated aqueous ammoniumchloride. The reaction mixture was phase separated and the aqueous layerwas extracted with ethyl acetate. The organic layers were combined anddried over anhydrous MgSO₄. The solid was filtered off and organicsolvent was evaporated off under vacuum. The crude product was purifiedby chromatography on silica gel using a mixture of hexane and ethylacetate as a gradient eluent. Yield of the titled compound was 2.4 g(66.5%).

¹H-NMR (400 MHz, CDCl₃): δ 7.352 (t, 1H), 7.173 (d, 1H), 7.082 (s, 1H),7.029 (d, 1H), 5.541-5.667 (m, 2H), 5.295-5.465 (m, 2H), 4.975 (heptet,1H), 4.471-4.512 (m, 1H), 4.101-4.135 (m, 1H), 4.007-4.034 (m, 1H),3.825-3.909 (m, 2H), 2.626-2.647 (m, 1H), 2.295-2.368 (m, 2H), 2.235 (t,2H), 2.036-2.172 (m, 2H), 1.906-1.967 (m, 1H), 1.799-1.834 (m, 1H),1.611-1.685 (m, 2H), 1.455-1.527 (m, 1H), 1.198 (d, 6H), 0.902-0.973 (m,18H), 0.532-0.650 (m, 12H)

¹³C-NMR (100 MHz, CDCl3): δ 173.159, 158.958, 133.553, 131.781 (q),130.023, 129.879, 129.363, 129.310, 123.932 (q), 117.962, 117.344 (q),111.135 (q), 79.290, 74.250, 72.678, 71.198, 67.335, 56.382, 51.448,43.175, 34.066, 26.552, 26.461, 24.905, 21.770, 6.749, 6.688, 4.843,4.638.

Comparative Example 15

Preparation of Travoprost Using Conjugate Addition Approach withoutMacrocyclic Lactonization

The product of Example 14 (0.8 g) was dissolved in 10 ml acetone and 2ml water, followed by addition of 0.1 g p-toluenesulfonic acidmonohydrate. The reaction solution was stirred at room temperature for 1hour and concentrated until two separate layers were observed. 30 mlethyl acetate was added for extraction and phase separation. The organiclayer was washed with saturated sodium bicarbonate solution and brine,dried over anhydrous magnesium sulfate, and subjected to vacuumevaporation for removal of the solvent until dryness. The crudeTravoprost was purified by column chromatography and then concentratedunder reduced pressure to provide 0.69 g of Travoprost. UPLC (ACQUITYUPLC HSS C18) ananlysis of the product showed that 4.95% 5,6-transisomer, 0.5% 15β-isomer and some other isomers were found.

Examples 16˜18 Preparation of Travoprost Using Conjugate AdditionApproach and Via Macrocyclic Lactonization Example 16(5Z)-7-((1R,2R,3R,5S)-2-((R,E)-4-(3-(trifluoromethyl)phenoxy)-3-(triethylsilyloxy)but-1-enyl)-5-hydroxy-3-(triethylsilyloxy)cyclopentyl)hept-5-enoicacid

(Z)-isopropyl7-((1R,2R,3R,5S)-3-((triethylsilyl)oxy)-2-((R,E)-3-((triethylsilyl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-5-hydroxycyclopentyl)hept-5-enoate(1.5 g from Example 14) in 10 mL methyl isobutyl ketone and 0.2 gCandida antarcitica lipase was added into 25 mL round-bottom flask. Thereaction mixture was stirred at room temperature for 3 days. Then, theLipase was filtered off and solvent was evaporated off under vacuum toobtain 1.5 g crude product.

Example 17(8aR,9R,10R,11aS,Z)-10-(triethylsilyloxy)-9-((3R,E)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

To a solution of (Z)-7-((IR,2R,3R,5S)-5-hydroxy-3-((triethylsilyl)oxy)-2-((R,E)-3-((triethylsilyl)oxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)cyclopentyl)hept-5-enoicacid (1.5 g, 2.19 mmole) and N,N-diisopropylethylamine (0.48 g fromExample 16) in methylene chloride (30 mL) at room temperature undernitrogen, benzoyl chloride (0.30 g, 2.13 mmole) was added and theresulting mixture was stirred for 1 hr at room temperature. The reactionmixture was cooled to −15 to −20° C. and a solution of4-dimethylaminopyridine (0.45 g, 3.69 mmole) in methylene chloride (5mL) was added dropwise over 5 minutes. The reaction mixture was furtherstirred for 30 minutes at −15 to −16° C. The reaction mixture wasquenched with saturated sodium bicarbonate solution (30 mL). The organiclayer was separated. The aqueous layer was extracted with methylenechloride (30 mL). The combined organic layer was dried over magnesiumsulfate, filtered and concentrated under reduced pressure to give 2.7 gof crude title compound. The crude title compound was purified by columnchromatography providing 0.9 g of the title compound. (61.6% yield).

Example 18(8aR,9R,10R,11aS,Z)-10-hydroxy-9-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

p-Toluenesulfonic acid monohydrate (0.20 g, 1.1 mmol) was add to astirred solution of (8aR,9R,10R,11aS,Z)-10-(triethylsilyloxy)-9-((3R,E)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-en-1-yl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(0.9 g from example 17) in methanol (50 mL). The mixture was stirred for2 hr at room temperature (TLC monitoring). Then, the reaction mixturewas quenched with saturated sodium bicarbonate aqueous solution (20 mL),and the methanol was removed under reduced pressure. The residue wasextracted with ethyl acetate. The organic layer was separated. Theaqueous layer was extracted with ethyl acetate. The combined organiclayer was dried over magnesium sulfate, filtered and concentrated underreduced pressure to give 1.1 g of the crude product. The crude productwas subjected to further purification by flash column chromatography toobtain 0.7 g of the product.

Determination of Isomer Content of the Product Before Crystallization:

A sample of the product before crystallization was hydrolyzed usingmethanol and 3N NaOH. After 2 h at 25° C., the mixture was acidified andextracted with ethyl acetate. After drying-concentration of theextracts, crude travprost acid was obtained. The crude travprost acidwas esterified using K₂CO₃ and 2-iodopropane in DMF. After 2 h at 60°C., water and ethyl acetate were added and extracted with ethyl acetate.After drying-concentration of the extracts, crude travprost wasobtained. UPLC (ACQUITY UPLC HSS C18) ananlysis of the crude productshowed that 0.02% 5,6-trans isomer and 0.01% 15β-isomer were found.

The product was recrystallized from a mixture of hexane and ethylacetate to give 0.5 g of title compound as a single crystalline form (mp113˜118° C.).

Determination of Isomer Content of the Crystalline Product:

A sample of the crystalline product was also subjected to the samemethod as described above for determining the isomer content. Crudetravoprost was obtained and UPLC (ACQUITY UPLC HSS C18) ananlysis of thecrude product showed that no 5,6-trans isomer, 15β-isomer or any otherisomers were found.

Comparative Examples 19˜23 Preparation of Travoprost and itsIntermediates Via Grubb's Catalysis Cyclization Comparative Example 19(2R,3R,4R)-2-allyl-4-(tert-butyldimethylsilyloxy)-3-((R,E)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)cyclopentanone

A 100 ml three-necked flask was flame dried and allowed to be cooledunder nitrogen.(R,E)-triethyl(4-(tributylstannyl)-1-(3-(trifluoromethyl)phenoxy)but-3-en-2-yloxy)silane (15.11 g, 23.8 mmol) and 20 mltetrahydrofuran were added to the reaction flask, followed by dropwiseaddition of n-butyl lithium (14.9 ml, 1.6 M in hexane) at −70° C. Asuspension solution of copper cyanide (2.13 g, 23.8 mmol) in 20 mltetrahydrofuran was cooled to −20° C., followed by dropwise addition ofmethyl lithium (11.9 ml, 2 M in ether). The homogenous organo-metallicsolution was cooled and added into the reaction flask while stirring for60 minutes. Then, a solution of(R)-2-allyl-4-(tert-butyldimethylsilyloxy)cyclopent-2-enone (3 g, 11.9mmol) in 20 ml tetrahydrofuran at −70° C. was added to the reactionmixture for 10 minutes. After being stirred for another 20 minutes, thereaction mixture was poured into a mixture of 9/1 (v/v) saturatedaqueous NH₄Cl/NH₄OH solution to be phase separated. The aqueous layerwas extracted with ethyl acetate. The organic layers were combined anddried over magnesium sulfate. The solid was filtered off and organicsolvent was evaporated off under vacuum. The crude product was purifiedby chromatography and then concentrated under reduced pressure toprovide 2.68 g of the title compound (37.7% yield).

¹H-NMR (400 MHz, CDCl₃):δ 7.376 (t, 1H), 7.201 (d, 1H), 7.088 (s, 1H),7.036 (d 1H), 5.691-5.753 (m, 3H), 5.024 (d, 2H), 4.561 (s, 1H),4.088-4.143 (m, 1H), 3.877 (d, 2H), 2.563-2.635 (m, 2H), 2.438-2.473 (m,1H), 2.261-2.311 (m, 1H), 2.070-2.200 (m, 2H), 0.970 (t, 9H), 0.867 (s,9H), 0.644 (q, 6H), 0.052 (s, 6H)

¹³C-NMR (100 MHz, CDCl₃):δ 214.838, 158.867, 134.874, 132.369, 131.982(q), 131.268, 129.932, 123.917 (q), 118.031, 117.370, 111.010, 72.929,72.625, 70.788, 53.528, 52.609, 74.501, 31.736, 25.671, 6.802, 4.866,−4.675 (d)

Comparative Example 20(1S,2R,3R,4R)-2-allyl-4-(tert-butyldimethylsilyloxy)-3-((RE)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)cyclopentanol

A 500 ml three-necked flask was flame dried and allowed to be cooledunder nitrogen.(2R,3R,4R)-2-allyl-4-(tert-butyldimethylsilyloxy)-3-((RE)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)cyclopentanone(2.68 g, 4.48 mmol) and 30 ml tetrahydrofuran were added to the reactionflask, followed by dropwise addition of L-Selectride (4 ml, 1M intetrahydrofuran) at −70° C. Then, the reaction mixture was warmed toroom temperature and quenched by 30 ml saturated aqueous ammoniumchloride. The reaction mixture was phase separated and the aqueous layerwas extracted with ethyl acetate. The organic layers were combined anddried over anhydrous magnesium sulfate. The solid was filtered off andorganic solvent was evaporated off under vacuum. The crude product waspurified by chromatography and then concentrated under reduced pressureto provide 2.5 g of the title compound (93% yield).

¹H-NMR (400 MHz, CDCl₃):δ 7.369 (t, 1H), 7.193 (d, 1H), 7.095 (s, 1H)7.038 (d 1H), 5.820-5.882 (m, 1H), 5.544-5.663 (m, 2H), 5.061 (d, 1H),4.965 (d, 1H), 4.500 (d, 1H), 4.150 (s, 1H), 4.033 (d, 1H), 3.841-3.918(m, 2H), 2.329-2.372 (m, 2H), 2.152-2.187 (m, 1H), 1.967-2.003 (m, 1H),1.798-1.834 (m, 1H), 1.551-1.572 (m, 1H), 0.964 (t, 9H), 0.869 (s, 9H),0.630 (q, 6H), 0.046 (s, 6H)

¹³C-NMR (100 MHz, CDCl₃):δ 158.935, 137.697, 133.401, 131.625 (q),130.327, 129.894, 123.936 (q), 117.970, 115.382, 108.862, 79.373,74.060, 72.640, 71.168, 60.115, 56.131, 50.803, 43.099, 33.034, 25.732,6.779, 4.843, −4.778 (d)

Comparative Example 21(1S,2R,3R,4R)-2-allyl-4-(tert-butyldimethylsilyloxy)-3-((R,E)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)cyclopentylhex-5-enoate

A 50 ml two-necked round-bottom flask was flame dried and allowed to becooled under nitrogen. (1S,2R,3R,4R)-2-allyl-4-(tert-butyldimethylsilyloxy)-3-((R,E)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)cyclopentanol(1 g, 1.66 mmol) in 10 ml of DMF, 0.05 g (0.33 mmol) of DMAP, 0.21 g(1.83 mmol) of 5-hexenoic acid, and 0.41 g (2.00 mmol) ofN,N′-dicyclohexylcarbodiimide were added to the reaction flask. Thereaction mixture was heated at 40° C. for 24 hours. The reaction wasquenched with 10 ml saturated aqueous sodium bicarbonate. The reactionmixture was phase separated and the aqueous layer was extracted withethyl acetate. The organic layers were combined and dried over anhydrousmagnesium sulfate. The solid was filtered off and organic solvent wasevaporated off under vacuum. The crude product was purified bychromatography and then concentrated under reduced pressure to provide1.05 g of the title compound (90.52% yield).

¹H-NMR (400 MHz, CDCl₃):δ 7.379 (t, 1H), 7.202 (d, 1H), 7.093 (s, 1H),7.038 (d 1H), 5.643-5.824 (m, 4H), 4.926-5.085 (m, 4H), 4.553 (d, 1H),3.865-3.925 (m, 3H), 3.203 (s, 1H), 2.293 (q, 2H), 2.114 (s, 3H), 1.912(s, 2H), 1.675-1.760 (m, 3H), 1.564-1.602 (m, 2H), 0.978 (t, 9H), 0.854(s, 9H), 0.655 (q, 6H), 0.026 (s, 6H)

¹³C-NMR (100 MHz, CDCl₃):δ 173.099, 158.943, 136.581, 132.521, 132.027,131.663 (q), 129.902, 123.938 (q), 117.985, 117.401, 115.769, 115.359,111.116, 73.855, 72.754, 70.879, 55.744, 55.357, 46.727, 42.233, 34.916,33.080, 31.653, 28.806, 25.755, 6.809, 4.904, −4.599 (d)

Comparative Example 22(8aR,9R,10R,11aS,Z)-10-(tert-butyldimethylsilyloxy)-9-((R,E)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

A 50 ml two-necked round-bottom flask was flame dried and allowed to becooled under nitrogen.(1S,2R,3R,4R)-2-allyl-4-(tert-butyldimethylsilyloxy)-3-((R,E)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)cyclopentylhex-5-enoate (0.2 g, 0.29 mmol) in 4 ml of dichloromethane, and 0.02 gof Grubb's catalyst were added to the reaction flask. The reactionmixture was heated at 40° C. for 18 hours. The reaction was quenchedwith 0.4 ml ethylamine with stirring for 1 hour. The reaction mixturewas phase separated and the aqueous layer was extracted with ethylacetate and 4 ml saturated aqueous sodium bicarbonate solution. Theorganic layers were combined and dried over anhydrous magnesium sulfate.The solid was filtered off and organic solvent was evaporated off undervacuum. The crude product was purified by chromatography and thenconcentrated under reduced pressure to provide 30 mg of the titlecompound (16% yield).

¹H-NMR (400 MHz, CDCl₃):δ 7.346 (t, 1H), 7.187 (d, 1H), 7.075 (s, 1H),7.023 (d 1H), 5.588-5.723 (m, 2H), 5.182-5.425 (m, 3H), 4.539 (q, 1H),2.189-2.557 (m, 4H), 2.012-2.085 (m, 2H), 1.873-1.920 (m, 2H),1.513-1.711 (m, 4H), 0.960 (t, 9H), 0.855 (s, 9H), 0.635 (q, 6H), 0.018(s, 6H)

¹³C-NMR (100 MHz, CDCl₃):δ 173.569, 158.912, 132.088, 131.944, 131.299(q), 129.902, 127.686, 125.295 (q), 118.008, 117.340, 111.040, 76.972,72.739, 71.950, 70.895, 55.547, 44.533, 41.581, 36.123, 34.006, 31.888,29.694, 28.806, 25.755, 6.817, 4.866, −4.588 (d)

Comparative Example 23 (8aR,9R,10R,11aS,Z)-10-hydroxy-9-((R,E)-3-hydroxy-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

(8aR,9R,10R,10R,11aS,Z)-10-(tert-butyldimethylsilyloxy)-9-((R,E)-3-(triethylsilyloxy)-4-(3-(trifluoromethyl)phenoxy)but-1-enyl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one (20 mg, 0.003 mmol) and 1 ml TBAF (1M intetrahydrofuran) was added into 10 ml round-bottom flask. The reactionmixture was stirred for 2 hours and quenched by 1 ml saturated NaHCO₃aqueous solution. Then, the mixture was phase separated and the aqueouslayer was extracted with ethyl acetate. The organic layers were combinedand dried over anhydrous MgSO₄. The solid was filtered off and organicsolvent was evaporated off under vacuum. The crude product was purifiedby chromatography and then concentrated under reduced pressure toprovide 10 mg of the title compound as an oil. (80% yield).

Determination of Isomer Content of the Product:

A sample of this product was hydrolyzed using methanol and 3N NaOH.After 2 h at 25° C., the mixture was acidified and extracted with ethylacetate. After drying-concentration of the extracts, crude travoprostacid was obtained. The crude travoprost acid was esterified using K₂CO₃and 2-iodopropane in DMF. After 2 h at 60° C., water and ethyl acetatewere added and phase separated, the aqueous layer was extracted withethyl acetate. After drying-concentration of the extracts, crudetravoprost was obtained. UPLC (ACQUITY UPLC HSS C18) ananlysis of thecrude product showed that 2.6% 5,6-trans isomer and some other isomerswere found.

¹H-NMR (400 MHz, CDCl₃): δ 7.387 (t, 1H), 7.227 (d, 1H), 7.145 (s, 1H),7.080 (m, 1H), 5.721-5.776 (m, 1H), 5.623-5.683 (m, 1H), 5.309-5.354 (m,1H), 5.222 (m, 2H), 4.527 (m, 1H), 3.947-4.033 (m, 2H), 3.812-3.874 (m,1H), 3.510 (br s, 1H), 3.409 (br s, 1H), 2.561-2.635 (m, 1H),2.098-2.418 (m, 6H), 1.587-1.870 (m, 5H)

¹³C-NMR (100 MHz, CDCl3): δ 173.471, 158.593, 135.147, 131.937 (q),131.534, 131.147, 130.099, 127.276, 123.856 (q), 118.099, 117.928 (q),111.446 (q), 75.935, 71.897, 70.993, 56.222, 44.981, 40.260, 36.040,26.711, 26.559, 25.269

Example 24˜30 Preparation of Latanoprost and its Intermediates ViaWittig Reaction Example 24(3aR,4R,5R,6aS)-4-((3R)-5-phenyl-3-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)-5-((tetrahydro-2H-pyran-2-yl)oxy)hexahydro-2H-cyclopenta[b]furan-2-one

p-Toluenesulfonic acid monohydrate (0.46 g, 2.4 mmol) was added to asolution of(3aR,4R,5R,6aS)-hexahydro-5-hydroxy-4-((R)-3-hydroxy-5-phenylpentyl)cyclopenta[h]furan-2-one(15.0 g, 49.3 mmol) and 3,4-dihydro-2H-pyran (12.4 g, 147.4 mmol) in THF(200 mL) at room temperature and the mixture was stirred for 2.5 hr (TLCmonitoring). Saturated aqueous solution of sodium bicarbonate (200 mL)was poured into reaction mixture and the reaction was stirred for 5minutes. The organic layer was separated and the aqueous layer wasextracted with ethyl acetate (200 mL). The combined organic layers weredried over magnesium sulfate, the solid was filtered off and thefiltrate was concentrated under reduced pressure to give 26.0 g of crudeproduct. The crude product was purified by column chromatography andthen concentrated under reduced pressure to provide 22.1 g of the titlecompound (95.0% yield).

¹H-NMR (400 MHz, CDCl₃): δ 7.209-7.247 (m, 2H), 7.117-7.171 (m, 3H),4.892-4.925 (m, 1H), 4.531-4.622 (m, 2H), 3.746-4.046 (m, 3H),3.604-3.630 (m, 1H), 3.397-3.454 (m, 2H), 1.134-2.765 (m, 26H)

¹³C-NMR (100 MHz, CDCl₃): δ177.706 (177.531, 177.425, 177.235), 142.434(142.403, 142.130, 142.100), 128.369, 128.240, 125.811 (125.689), 98.797(98.607, 98.152), 97.742 (97.681, 95.692, 95.624), 84.185 (84.155,84.094, 84.071), 82.887 (82.705), 79.813 (79.677), 76.360 (76.314,76.086, 76.011), 63.562 (62.948, 62.454, 61.877), 53.277 (52.943),52.086 (51.623), 42.985 (42.894, 42.484, 42.416), 39.000 (38.924,36.670, 36.609), 36.093 (36.040, 35.546, 35.508), 33.019 (32.875,31.751, 31.615), 31.895 (31.258), 31.417 (30.491), 31.334 (31.296,30.749, 30.719), 28.867 (28.556), 28.677 (28.343), 25.428, 20.517(20.434, 20.024), 19.402 (19.371, 18.954, 18.916)

Example 25(3aR,4R,5R,6aS)-4-((3R)-5-phenyl-3-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)-5-((tetrahydro-2H-pyran-2-yl)oxy)hexahydro-2H-cyclopenta[b]furan-2-ol

(3aR,4R,5R,6aS)-4-((3R)-5-phenyl-3-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)-5-((tetrahydro-2H-pyran-2-yl)oxy)hexahydro-2H-cyclopenta[b]furan-2-one(22.0 g, 46.6 mmol) was dissolved in toluene (200 mL), followed bycooling to −70° C., and DIBAL (1.0M in hexane, 60 mL, 60.0 mmol) wasadded dropwisely. Then the reaction was quenched by adding saturatedaqueous solution of ammonium chloride (10 mL) at −70° C. The resultingmixture was poured into 200 mL of a 2M sodium bisulfate aqueous solutionat room temperature and the stirring was continued for 30 minutes. Afterseparation of the organic layers, toluene (200 mL) was added to theaqueous layer. The combined organic layers were concentrated underreduced pressure to give 30.0 g of crude title compound.

¹H-NMR (400 MHz, CDCl₃): δ 7.237-7.274 (m, 2H), 7.133-7.205 (m, 3H),5.410-5.609 (m, 1H), 4.587-4.729 (m, 3H), 3.779-3.935 (m, 3H),3.603-3.688 (m, 1H), 3.446-3.504 (m, 2H), 1.183-2.833 (m, 26H)

¹³C-NMR (100 MHz, CDCl₃): δ142.661 (142.593, 142.297, 142.191), 128.392,128.262, 125.811 (125.765, 125.682, 125.613), 101.605 (101.537, 101.469,101.400), 98.182 (97.833, 97.689, 97.499), 96.224 (96.155, 95.973,95.874), 85.726 (85.460, 85.210, 85.119), 80.967 (80.899, 80.861,80.557), 76.678 (76.587, 76.420, 76.071), 63.251 (63.137, 62.910,62.887), 62.310 (62.105, 62.044, 62.006), 53.247 (52.594, 52.564),51.554 (51.516, 51.433, 51.380), 47.645 (47.304, 45.346, 44.799) 42.142(42.112, 38.567, 38.545), 41.960 (41.899, 41.095, 41.042), 40.769(39.562), 36.715 (36.624, 35.417, 35.326), 33.155 (33.133, 33.004),31.987 (31.918, 31.243, 31.182), 30.871 (30.802, 30.476, 30.385), 29.163(28.928, 28.624, 28.373), 25.482 (25.436, 25.292), 20.275 (20.206,20.070, 19.994), 19.523 (19.295, 19.045, 18.931)

Example 26(Z)-7-((1R,2R,3R,5S)-5-hydroxy-2-((3R)-5-phenyl-3-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)-3-((tetrahydro-2H-pyran-2-yl)oxy)cyclopentyl)hept-5-enoic acid

A suspension of (4-carboxybutyl)triphenylphosphonium bromide (84.0 g,189.5 mmol) and potassium tert-butoxide (44.0 g, 392.1 mmol) in THF (700mL) was cooled to −20° C. for 30 min. A solution of(3aR,4R,5R,6aS)-4-((3R)-5-phenyl-3-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)-5-((tetrahydro-2H-pyran-2-yl)oxy)hexahydro-2H-cyclopenta[b]furan-2-ol(30 g from Example 25) in THF (50 mL) at −20° C. was added and thereaction mixture was stirred for 16 hr. Then saturated aqueous solutionof ammonium chloride (500 mL) was added and the resulting suspension wasstirred for 30 min at room temperature. After separation of the organiclayers, the aqueous layer was adjusted to have a pH of 6.0 by additionof a 2M sodium bisulfate solution and extracted with ethyl acetate (300mL). The combined organic layers were dried over magnesium sulfate andconcentrated under reduced pressure to give 54.0 g of crude titlecompound.

¹H-NMR (400 MHz, CDCl₃): δ 7.248-7.289 (m, 2H), 7.140-7.211 (m, 3H),5.463-5.577 (m, 1H), 5.314-5.388 (m, 1H), 4.666-4.714 (m, 1H),4.609-4.641 (m, 1H), 4.084-4.119 (m, 1H), 3.913-4.054 (m, 2H),3.794-3.874 (m, 1H), 3.665-3.740 (m, 1H), 3.465-3.539 (m, 2H),2.555-2.834 (m, 2H), 1.311-2.383 (m, 30H)

¹³C-NMR (100 MHz, CDCl3): δ 177.789 (177.364), 142.616 (142.517,142.327, 142.214), 129.856 (129.788, 129.697, 129.606), 129.226(129.151, 129.105, 129.037), 128.392, 128.308 (128.293, 128.270),125.818 (125.780, 125.689, 125.659), 98.895 (98.622), 97.393 (96.914,96.641, 96.558), 82.796 (82.766, 82.014, 81.992), 77.195 (76.231,76.086), 74.728 (74.758, 74.675), 63.547 (63.456, 62.818, 62.781),62.644 (62.598, 62.378, 62.295), 52.040 (51.820), 51.737 (51.463),49.998 (49.968), 49.869 (49.839), 40.548 (40.510), 36.753 (36.708),33.338 (33.292, 33.087, 33.019), 32.070 (32.040, 31.744), 31.569(31.440, 31.326, 31.296), 31.136 (31.098, 30.787), 29.580 (29.375,28.950, 28.730), 27.341 (27.189, 27.007, 26.871), 26.499 (26.370),25.444 (25.398), 24.677 (24.563), 20.426 (20.373), 19.326 (19.288)

Example 27(8aR,9R,10R,11aS,Z)-9-((3R)-5-phenyl-3-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)-10-((tetrahydro-2H-pyran-2-yl)oxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

A solution of(Z)-7-((1R,2R,3R,5S)-5-hydroxy-2-((3R)-5-phenyl-3-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)-3-((tetrahydro-2H-pyran-2-yl)oxy)cyclopentyl)hept-5-enoicacid (52 g from Example 26) in xylene (250 mL) was treated with2,2′-dipyridyl disulfide (28.9 g, 131.2 mmol) and triphenylphosphine(39.2 g, 149.5 mmol). This mixture was then stirred for 2 hr at roomtemperature under an atmosphere of nitrogen. The resulting mixture washeated to 80° C. for 18 hr (TLC monitoring), followed by removal ofxylene under reduced pressure. The residue was diluted with saturatedaqueous solution of sodium bicarbonate (200 mL) and extracted with ethylacetate (200 mL). The organic layer was dried over magnesium sulfate andconcentrated under reduced pressure to give 80.0 g of crude product. Thecrude product was purified by column chromatography providing 17.1 g ofthe title compound (68.0% yield, 3 steps).

¹H-NMR (400 MHz, CDCl₃): δ 7.240-7.282 (m, 2H), 7.153-7.218 (m, 3H),5.245-5.350 (m, 2H), 5.102-5.117 (m, 1H), 4.560-4.695 (m, 2H),3.890-3.978 (m, 2H), 3.808-3.876 (m, 1H), 3.632-3.715 (m, 1H),3.442-3.520 (m, 2H), 2.580-2.815 (m, 2H), 1.352-2.507 (m, 30H)

¹³C-NMR (100 MHz, CDCl3): δ 173.873 (173.843, 173.797, 173.759), 142.722(142.593, 142.464, 142.320), 131.139 (130.995), 128.392 (128.361),128.300 (128.262), 127.632 (127.837, 127.868), 125.788 (125.727,125.667, 125.606), 100.413 (100.391, 98.129, 97.871), 97.840 (97.704,96.504, 96.391), 79.085 (84.231, 84.254), 76.375 (76.542, 76.694),73.695 (73.582), 63.077 (62.970, 62.932, 62.856), 62.796 (62.758,62.507, 62.393), 49.110, 44.974 (44.928, 44.609, 44.564), 39.843, 37.224(37.201), 36.882 (36.814), 36.063, 35.516 (35.440), 32.047 (32.017,31.956), 31.417 (31.273), 31.076 (30.985, 30.780, 30.711), 27.129,26.681, 26.552 (26.506), 25.497, 25.428 (25.406), 20.176 (20.100,20.047), 20.024 (19.850, 19.561, 19.493)

Example 28(8aR,9R,10R,11aS,Z)-10-hydroxy-9-((R)-3-hydroxy-5-phenylpentyl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

p-Toluenesulfonic acid monohydrate (0.34 g, 1.8 mmol) was added to astirred solution of(8aR,9R,10R,11aS,Z)-9-((3R)-5-phenyl-3-((tetrahydro-2H-pyran-2-yl)oxy)pentyl)-10-((tetrahydro-2H-pyran-2-yl)oxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(17.0 g, 31.4 mmol) in methanol (170 mL). The mixture was stirred for 2hr at room temperature (TLC monitoring). Then, the reaction mixture wasquenched with saturated sodium bicarbonate aqueous solution (200 mL),and the methanol was removed under reduced pressure. The residue wasextracted with ethyl acetate (200 mL). The organic layer was separated.The aqueous layer was extracted with ethyl acetate (200 mL). Thecombined organic layers were dried over magnesium sulfate, filtered andconcentrated under reduced pressure to give 16.3 g of crude product. Thecrude product was purified by column chromatography providing 9.2 g ofthe product (78.6% yield). The product was crystallized from a mixtureof hexane and ethyl acetate to give 8.1 g white crystals (mp 114˜118°C.).

The x-ray powder diffraction pattern of crystalline title compound hascharacteristic peaks expressed in degrees 2θ at approximately 9.0, 10.6,14.5, 15.1, 17.3, 18.2, 19.6, 21.0, 21.2, 23.4, 27.69, 37.8, 44.1.

Determination of Isomer Content:

Four samples (the product before crystallization, the product of thefirst crystallization, the filtrate of the first crystallization, andthe product of the second crystallization) were hydrolyzed usingmethanol and 3N NaOH. After 2 h at 25° C., the mixture was acidified andextracted with ethyl acetate. After drying-concentration of theextracts, crude Latanoprost acid was obtained. The crude Latanoprostacid was esterified using K₂CO₃ and 2-iodopropane in DMF. After 2 h at60° C., water and ethyl acetate were added and phase separated, theaqueous layer extracted with ethyl acetate. After drying-concentrationof the extracts, crude Latanoprost was obtained. HPLC (Phenomenex Luna 5μm silica) ananlysis of the crude product showed the following results:

Sample 5,6-trans isomer 15β-isomer Before crystallization 0.10% 0.06%After 1^(st) crystallzation 0.01% not detectable 1^(st) filtrate 0.16%0.12% After 2^(nd) crystallization not detectable not detectable

¹H-NMR (400 MHz, CDCl₃): δ 7.239-7.276 (m, 2H), 7.140-7.186 (m, 3H),5.275-5.338 (m, 1H), 5.190-5.243 (m, 1H), 5.112 (m, 1H), 3.792-3.853 (m,1H), 3.626 (br s, 1H), 3.477-3.489 (m, 1H), 3.070 (br s, 1H),2.737-2.810 (m, 2H), 2.603-2.678 (m, 1H), 1.443-2.455 (m, 17H)

¹³C-NMR (100 MHz, CDCl3): δ 173.880, 142.092, 131.162, 128.422, 128.399,127.648, 125.849, 77.392, 74.083, 71.525, 52.033, 46.165, 40.920,39.023, 36.100, 34.765, 32.131, 27.827, 27.485, 26.696, 25.428

Example 29(Z)-7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoicacid

A solution of(8aR,9R,10R,11aS,Z)-10-hydroxy-9-((R)-3-hydroxy-5-phenylpentyl)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(1.0 g, product after the second crystallization of Example 28) in 10 mL2-propanol was treated with 3N potassium hydroxide aqueous solution (2.7mL). This mixture was stirred at 50° C. for 2 hr. The reaction mixturewas cooled and further adjusted to have a pH of 8.5±0.2 with 3Nhydrochloric acid aqueous solution. Most of the solvent was removedunder reduced pressure. The residue was diluted with saturated aqueoussolution of sodium bicarbonate (20 mL) and ethyl acetate (20 mL). Themixture was stirred at room temperatures for 5 minutes. The organicphase and the aqueous phase were separately collected. The aqueous layerwas adjusted to have a pH of 3.0±0.2 with 3N hydrochloric acid aqueoussolution at room temperature and extracted with ethyl acetate (20 mL).The organic layer was dried over magnesium sulfate and concentratedunder reduced pressure to give 1.3 g of crude Latanoprost acid.

Determination of Isomer Content of the Product:

A sample of this product was esterified using K₂CO₃ and 2-iodopropane inDMF. After 2 h at 60° C., water and ethyl acetate were added and phaseseparated, the aqueous layer extracted with ethyl acetate. Afterdrying-concentration of the extracts, crude Latanoprost was obtained.HPLC (Phenomenex Luna 5 μm silica) ananlysis of the crude product showedthat no isomer was detectable.

¹H-NMR (400 MHz, CDCl₃): δ 7.253-7.282 (m, 2H), 7.157-7.194 (m, 3H),5.455-5.506 (m, 1H), 5.342-5.394 (m, 1H), 4.142-4.152 (m, 1H), 3.936 (m,1H), 3.664-3.711 (m, 1H), 2.754-2.813 (m, 1H), 2.618-2.678 (m, 1H),2.327 (t, 2H), 2.241 (t, 2H), 2.133 (q, 2H), 1.496-1.892 (m, 10H),1.307-1.382 (m, 2H)

¹³C-NMR (100 MHz, CDCl3): δ 177.382, 142.178, 129.555, 129.512, 128.487,125.902, 78.493, 74.354, 71.477, 52.234, 51.536, 42.396, 38.634, 35.077,32.923, 31.982, 28.893, 26.490, 26.229, 24.500

Example 30 (Z)-isopropyl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((R)-3-hydroxy-5-phenylpentyl)cyclopentyl)hept-5-enoate (Latanoprost)

A solution of crude Latanoprost acid (1.3 g from Example 29) in DMF (13mL) was treated with K₂CO₃ (1.38 g, 1.0 mmol) and 2-iodopropane (1.13 g,6.6 mmol). This mixture was then stirred at 80° C. for 2 hr under anatmosphere of nitrogen (TLC monitoring). Water (40 mL) and ethyl acetate(40 mL) were added and the mixture was stirred for 10 min. The aqueouslayer was separated and extracted with ethyl acetate (40 mL), and thecombined organic layer was dried over magnesium sulfate and concentratedunder reduced pressure to give 1.1 g of crude Latanoprost. The crudeLatanoprost could be purified by column chromatography and thenconcentrated under reduced pressure to provide 0.7 g of Latanoprost(60.3% yield, 2 steps, HPLC (Phenomenex Luna 5 μm silica) ananlysis ofthe product showed that no isomer was detectable).

¹H-NMR (400 MHz, CDCl₃):δ 7.262-7.293 (m, 2H), 7.165-7.206 (m, 3H),5.433-5.484 (m, 1H), 5.360-5.411 (m, 1H), 4.993 (heptet, 1H),4, 158 (m,1H), 3.939 (m, 1H), 3.659 (m, 1H), 2.766-2.824 (m, 3H), 2.089-2.702 (m,8H), 1.314-1.898 (m, 12H), 1.221 (d, 6H)

¹³C-NMR (100 MHz, CDCl₃):δ 173.476, 142.072, 129.590, 129.322, 128.393,125.806, 78.788, 74.709, 71.292, 67.651, 52.895, 51.883, 42.490, 39.046,35.793, 34.033, 32.108, 29.631, 26.898, 26.613, 24.913, 21.819

The crude Latanoprost could also be purified via silylation anddesilylation as described in Examples 11 and 12. HPLC (Phenomenex Luna 5μm silica) ananlysis of the product showed that no isomer or impuritywas detectable.

¹H-NMR (400 MHz, CDCl₃): δ 7.257-7.294 (m, 2H), 7.172-7.190 (m, 3H),5.422-5.484 (m, 1H), 5.326-5.387 (m, 1H), 5.001 (heptet, 1H),4.074-4.119 (m, 1H), 3.676-3.769 (m, 2H), 2.578-2.733 (m, 2H),2.238-2.306 (m, 2H), 2.067-2.191 (m, 4H), 1.586-1.799 (m, 7H),1.501-1.552 (m, 2H), 1.370-1.437 (m, 3H), 1.222 (d, 6H), 0.932-0.999 (m,27H), 0.546-0.645 (m, 18H)

¹³C-NMR (100 MHz, CDCl₃): δ 173.197, 142.692, 130.122, 128.953, 128.293,128.278, 125.606, 76.238, 72.352, 71.768, 67.297, 50.264, 48.162,44.230, 39.121, 34.484, 34.241, 31.728, 28.062, 26.764, 25.846, 25.041,21.823, 6.991, 6.885, 6.870, 5.177, 4.972, 4.942

Example 31˜37 Preparation of Tafluprost and its Intermediates Example 31(3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-5-((tetrahydro-2H-pyran-2-yl)oxy)hexahydro-2H-cyclopenta[b]furan-2-ol

(3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-phenoxybut-1-enyl)-hexahydro-5-(tetrahydro-2H-pyran-2-yloxy)cyclopenta[b]furan-2-one(47.0 g, 0.11 mol) was dissolved in toluene (500 mL), followed bycooling to −70° C., and DIBAL (1.0M in Hexane, 172 mL, 0.16 mol) wasadded dropwisely. Then the reaction was quenched by adding saturatedaqueous solution of ammonium chloride (25 mL) at −70° C. The resultingmixture was poured into a 2M sodium bisulfate aqueous solution (500 mL)at room temperature and stirring was continued for 30 minutes. Afterseparation of the organic layers, 500 mL of toluene was added to theaqueous layer. The combined organic layers were concentrated underreduced pressure to give 48 g of crude title compound.

¹H-NMR (400 MHz, CDCl₃): δ 7.266-7.316 (m, 2H), 6.971-7.010 (m, 1H),6.892-6.914 (m, 2H), 6.078-6.222 (m, 1H), 5.736-5.912 (m, 1H),5.516-5.644 (m, 1H), 4.517-4.699 (m, 2H), 4.139-4.211 (m, 2H),3.725-4.064 (m, 2H), 3.398-3.493 (m, 1H), 3.339 (br s, 1H), 2.337-2.554(m, 2H), 1.905-2.112 (m, 3H), 1.353-1.808 (m, 7H)

¹³C-NMR (100 MHz, CDCl₃):δ 157.963 (157.895), 138.050, 129.576, 123.617,121.826, 118.220 (t), 114.706, 101.028 (100.899), 99.821 (95.935),83.168 (83.009), 80.291 (79.935), 69.498 (t), 62.401 (61.665), 54.386(53.733), 45.733 (44.951), 38.932 (38.818), 36.693, 30.613 (30.461),25.337 (25.315), 19.485 (18.779)

Example 32(Z)-7-((1R,2R,3R,5S)-2-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-5-hydroxy-3-((tetrahydro-2H-pyran-2-yl)oxy)cyclopentyl)hept-5-enoicacid

A suspension of (4-carboxybutyl)triphenylohosphonium bromide (198.0 g,0.45 mol.) and potassium-tert butoxide (102.0 g, 0.91 mol.) in THF (1 L)was cooled to −20° C. for 30 min, and a solution of (3aR,4R,5R,6aS)-4-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-5-((tetrahydro-2H-pyran-2-yl)oxy)hexahydro-2H-cyclopenta[b]furan-2-ol(48.0 g from example 31) in THF (100 mL) at −20° C. was added and thereaction mixture was stirred for 3 hr. Then saturated aqueous solutionof ammonium chloride (600 mL) was added and the resulting suspension wasstirred for 30 min at room temperature. After separation of the organiclayers, the aqueous layer was adjusted to a pH of 6.0 by addition of a2M sodium bisulfate solution and extracted with ethyl acetate (600 mL).The combined organic layers were dried over magnesium sulfate andconcentrated under reduced pressure to give 145.0 g of crude titlecompound.

Determination of Isomer Content of the Product:

A sample of this product was esterified using K₂CO₃ and 2-iodopropane inDMF. After 4 h at 60° C., water and ethyl acetate were added and phaseseparated, the aqueous layer was extracted with ethyl acetate. Afterdrying-concentration of the extracts, crude 11-protected Tafluprost wasobtained. The crude 11-protected Tafluprost was deprotected using 3N HClin THF and water. After 1 h at 25° C., saturated aqueous solution ofsodium bicarbonate was added and extracted with ethyl acetate. Afterdrying-concentration of the extracts, crude Tafluprost was obtained.HPLC (Phenomenex Luna 5 μm silica) ananlysis of the crude product showedthat 2.8% 5,6-trans isomer was found.

¹H-NMR (400 MHz, CDCl₃): δ 7.244-7.302 (m, 2H), 6.941-6.984 (m, 1H),6.879-6.901 (m, 2H), 6.085-6.187 (m, 1H), 5.730-5.875 (m, 1H),5.305-5.435 (m, 2H), 4.608-4.651 (m, 1H), 4.034-4.195 (m, 3H),3.739-3.853 (m, 1H), 3.378-3.458 (m, 1H), 2.500-2.670 (m, 1H),2.226-2.331 (m, 4H), 2.071-2.176 (m, 3H), 1.399-1.783 (m, 12H)

¹³C-NMR (100 MHz, CDCl3):δ 177.516 (177.448), 157.971 (157.926), 138.983(dt), 129.568, 128.619, 128.498, 123.754 (t), 121.780 (121.750), 118.235(t), 114.706, 98.387 (96.467), 82.174 (80.868), 72.800, 69.528 (t),62.743 (61.558), 52.405, 49.907, 41.528, 33.444, 26.544, 25.724, 25.550,25.337, 24.639, 18.893

Example 33(8aR,9R,10R,11aS,Z)-9-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-10-((tetrahydro-2H-pyran-2-yl)oxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

A solution of(Z)-7-((R,2R,3R,5S)-2-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-5-hydroxy-3-((tetrahydro-2H-pyran-2-yl)oxy)cyclopentyl)hept-5-enoicacid (145.0 g from Example 32) in xylene (2 L) was treated with2,2′-dipyridyl disulfide (90.0 g, 0.41 mol.) and triphenylphosphine(123.0 g, 0.47 mol.). This mixture was then stirred for 1 hr at roomtemperature under an atmosphere of nitrogen. The resulting mixture washeated to 80° C. for 18 hr (TLC monitoring), followed by removal ofxylene under reduced pressure. The residue was diluted with saturatedaqueous solution of sodium bicarbonate (1.6 L) and extracted with ethylacetate (1.6 L). The organic layer is dried over magnesium sulfate andconcentrated under reduced pressure to give 322.0 g of crude product.The crude product was purified by column chromatography providing 26.0 gof the title compound (48% yield, 3 steps).

Determination of Isomer Content of the Product:

A sample of this product was hydrolyzed using methanol and 3N NaOH.After 2 h at 25° C., the mixture was acidified and extracted with ethylacetate. After drying-concentration of the extracts, crude 1-protectedTafluprost acid was obtained. The crude 1-protected Tafluprost acid wasesterified using K₂CO₃ and 2-iodopropane in DMF. After 2 h at 60° C.,water and ethyl acetate were added and phase separated, the aqueouslayer was extracted with ethyl acetate. After drying-concentration ofthe extracts, crude 1-protected Tafluprost was obtained. The crude11-protected Tafluprost was deprotected using 3N HCl in THF and water.After 1 h at 25° C., saturated aqueous solution of sodium bicarbonatewas added and phase separated, the aqueous layer was extracted withethyl acetate. After drying-concentration of the extracts, crudeTafluprost was obtained. HPLC (Phenomenex Luna 5 μm silica) ananlysis ofthe crude product showed that 0.4% 5,6-trans isomer was found and HPLC(Chiralcel OD-H) ananlysis of the crude product showed that 0.1%enantiomer was found.

¹H-NMR (400 MHz, CDCl₃): δ 7.257-7.306 (m, 2H), 6.984 (t, 1H), 6.89 (d,2H), 6.061-6.157 (m, 1H), 5.816-5.974 (m, 1H), 5.315-5.371 (m, 1H),5.247-5.305 (m, 2H), 4.589-4.632 (m, 1H), 4.141-4.247 (m, 2H),3.893-4.047 (m, 1H), 3.733-3.822 (m, 1H), 3.374-3.456 (m, 1H),2.536-2.672 (m, 2H), 2.334-2.416 (m, 3H), 2.179-2.253 (m, 1H),2.051-2.108 (m, 1H), 1.330-1.895 (m, 11H)

¹³C-NMR (100 MHz, CDCl₃):δ 173.546 (173.448), 157.956 (157.888), 137.872(t), 131.572, 129.568, 127.048, 124.930 (t), 121.811, 118.061 (t),114.691, 99.388 (96.117), 81.172 (78.204), 72.451 (72.010), 69.544 (t),62.629, 61.308, 44.852, 37.816, 36.040, 30.643, 30.529, 26.734 (26.529),25.383, 25.322, 18.726

Example 34(8aR,9R,10R,11aS,Z)-9-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-10-hydroxy-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

p-toluenesulfonic acid monohydrate (10.37 g, 54.5 mmol) was add to astirred solution of(8aR,9R,10R,11aS,Z)-9-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-10-((tetrahydro-2H-pyran-2-yl)oxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(26.0 g from example 33) in methanol (200 mL). The mixture was stirredfor 2 hr at room temperature (TLC monitoring). Then, the reactionmixture was quenched with saturated sodium bicarbonate aqueous solution(300 mL), and the methanol was removed under reduced pressure. Theresidue was extracted with ethyl acetate (200 mL). The organic layer wasseparated. The aqueous layer was extracted with ethyl acetate (200 mL).The combined organic layers were dried over magnesium sulfate, filteredand concentrated under reduced pressure to give 30.0 g of crude product.The crude product was purified by column chromatography providing 20.0 gof the titled compound (90.0% yield).

¹H-NMR (400 MHz, CDCl₃): δ 7.273-7.313 (m, 2H), 6.976-7.018 (m, 1H),6.894-6.919 (m, 2H), 6.050-6.100 (m, 1H), 5.836-5.931 (m, 1H),5.305-5.373 (m, 1H), 5.214-5.233 (m, 2H), 4.206 (t, 2H), 3.901-3.961 (m,1H), 2.536-2.612 (m, 1H), 2.340-2.453 (m, 4H), 2.176-2.238 (m, 3H),1.787-1.932 (m, 3H), 1.620-1.723 (m, 2H)

¹³C-NMR (100 MHz, CDCl₃):δ 173.463, 157.880, 137.492 (t), 131.633,129.743, 127.018, 125.378 (t), 121.902, 118.023 (t), 114.767, 76.094,72.246, 69.399 (t), 55.843, 45.649, 40.594, 36.040, 26.734, 26.582,25.322

Example 35(6Z,8aR,9R,10R,11aS)-9-((E)-3,3-difluoro-4-phenoxybut-1-enyl)-2,3,4,5,8,8a,9,10,11,11a-decahydro-2-oxocyclopenta[b]oxecin-10-yl4- phenylbenzoate

A solution of(8aR,9R,10R,11aS,Z)-9-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-10-hydroxy-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(20.0 g, from Example 34) in THF (200 mL) was treated with triethylamine(20.6 g, 0.20 mol), 4-(dimethylamino)pyridine (0.62 g, 5.09 mmol) andbiphenyl-4-carbonyl chloride (33.0 g, 0.15 mol). This mixture was thenstirred for 18 hr at room temperature under an atmosphere of nitrogen.Saturated aqueous solution of sodium bicarbonate (200 mL) was pouredinto the reaction mixture and the resulting mixture was stirred for 5minutes. The organic layer was separated and the aqueous layer wasextracted with ethyl acetate (400 mL). The combined organic layers weredried over magnesium sulfate, the solid was filtered off and filtratewas concentrated under reduced pressure to give 40.0 g of crude product.The crude product was purified by column chromatography and thenconcentrated under reduced pressure to provide 20.0 g of the titlecompound (69.0% yield). The residue was crystallized from methanol togive white crystalline compound (mp 105˜109° C.). The x-ray powderdiffraction pattern of crystalline title compound has characteristicpeaks expressed in degrees 2θ at approximately 5.0, 6.2, 7.6, 9.5, 10.1,11.5, 12.6, 13.7, 15.2, 18.0, 19.4, 21.2, 23.1, 23.6, 24.4, 25.7, 28.0,37.9, 44.1.

Determination of Isomer Rate of the Product:

Four samples (the product before crystallization, the product of thefirst crystallization, the filtrate of the first crystallization, andthe product of the second crystallization) were hydrolyzed usingmethanol and 3N NaOH. After 2 h at 25° C., the mixture was acidified andextracted with ethyl acetate. After drying-concentration of theextracts, crude Latanoprost acid was obtained. The crude Latanoprostacid was esterified using K₂CO₃ and 2-iodopropane in DMF. After 2 h at60° C., water and ethyl acetate were added and phase separated, theaqueous layer was extracted with ethyl acetate. Afterdrying-concentration of the extracts, crude Latanoprost was obtained.HPLC (Phenomenex Luna 5 μm silica and Chiralcel OD-H) analysis of thecrude product showed the following results:

Sample 5,6-trans isomer enantiomer before crystallization 0.44%  0.1%After 1^(st) crystallization 0.03% not detectable 1^(st) filtrate 0.87%0.17% After 2^(nd) crystallization not detectable not detectable

¹H-NMR (400 MHz, CDCl₃): δ 8.055 (d, 2H), δ7.601 (d, 4H), δ7.477 (t,2H), δ7.389-7.425 (m, 1H), 7.206-7.258 (m, 2H), 6.948 (t, 1H), 6.832 (d,2H) 6.161-6.222 (m, 1H), 5.890-5.984 (m, 1H), 5.380-5.424 (m, 1H),5.321-5.371 (m, 2H), 5.166-5.224 (m, 1H), 4.126-4.199 (m, 2H),2.805-2.882 (m, 2H), 2.394-2.507 (m, 3H), 2.154-2.296 (m, 2H),1.949-1.991 (m, 3H), 1.802-1.855 (m, 1H), 1.647-1.769 (m, 1H)

¹³C-NMR (100 MHz, CDCl₃):δ 173.401, 166.042, 157.833, 145.780, 139.924,136.440 (t), 131.856, 130.099, 129.541, 128.941, 128.634, 128.205,127.279, 127.044, 126.763, 125.628 (t), 121.738, 118.000 (t), 114.668,77.779, 72.416, 69.452 (t), 52.811, 44.997, 38.404, 36.040, 26.818,26.666, 25.444

Example 36(Z)-7-((1R,2R,3R,5S)-2-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-3,5-dihydroxycyclopentyl)hept-5-enoicacid (Tafluprost acid)

A solution of(6Z,8aR,9R,10R,11aS)-9-((E)-3,3-difluoro-4-phenoxybut-1-enyl)-2,3,4,5,8,8a,9,10,11,11a-decahydro-2-oxocyclopenta[b]oxecin-10-yl4-phenylbenzoate (10.0 g from Example 35) in methanol (60 mL) and THF(160 mL) was treated with 3N sodium hydroxide aqueous solution (80 mL).This mixture was stirred at room temperature under an atmosphere ofnitrogen for 2 hr. The reaction mixture was further adjusted to a pH of8.5±0.2 with 3N hydrochloric acid aqueous solution and most of solventwas removed under reduced pressure. The residue was diluted withsaturated aqueous solution of sodium bicarbonate (200 mL) and ethylacetate (200 mL). The mixture was stirred at room temperatures for 5minutes. The organic phase and the aqueous phase were separatelycollected. The aqueous layer was adjusted to a pH of 3.0±0.2 with 3Nhydrochloric acid aqueous solution at room temperature and extractedwith ethyl acetate (200 mL). The organic layer was dried over magnesiumsulfate and concentrated under reduced pressure to give 12 g of crudeTafluprost acid.

Determination of Isomer Content of the Product:

A sample of this product was esterified using K₂CO₃ and 2-iodopropane inDMF. After 2 h at 60° C., water and ethyl acetate were added and themixture was extracted with ethyl acetate. After drying-concentration ofthe extracts, crude Tafluprost was obtained. HPLC (Phenomenex Luna 5 μmsilica) analysis of the crude product showed that no isomer wasdetectable, and HPLC (Chiralcel OD-H) analysis of the crude productshowed that no enantiomer was detectable.

¹H-NMR (400 MHz, CDCl₃): δ 7.264-7.311 (m, 2H), 6.972-7.014 (m, 1H),6.897-6.926 (m, 2H), 6.054-6.127 (m, 1H),5.750-5.845 (m, 1H),5.324-5.417 (m, 2H), 4.149-4.218 (m, 3H), 4.029 (m, 1H), 2.435-2.495 (m,1H), 2.279-2.370 (m, 3H), 2.014-2.194 (m, 4H), 1.819-1.850 (m, 1H),1.562-1.728 (m, 3H)

¹³C-NMR (100 MHz, CDCl₃):δ 177.972, 157.926, 138.547 (t), 129.910,129.606, 128.779, 123.723 (t), 121.826, 118.167 (t), 114.774, 77.863,73.324, 69.437 (t), 55.532, 50.393, 42.788, 32.935, 26.377, 25.694,24.427

Example 37 (Z)-isopropyl7-((1R,2R,3R,5S)-2-((E)-3,3-difluoro-4-phenoxybut-1-en-1-yl)-3,5-dihydroxycyclopentyl)hept-5-enoate (Tafluprost)

A solution of crude Tafluprost acid (12.0 g from Example 36) in DMF (100mL) was treated with K₂CO₃ (21.1 g, 0.12 mol.) and 2-iodopropane (11.4g, 0.08 mol.). This mixture was then stirred at 80° C. for 2 hr under anatmosphere of nitrogen (TLC monitoring). Water (100 mL) and ethylacetate (100 mL) was added and the mixture was stirred for 10 min. Theaqueous layer was separated and extracted with ethyl acetate (100 mL),the combined organic layer was dried over magnesium sulfate andconcentrated under reduced pressure to give 14.0 g of crude Tafluprost.The crude Tafluprost was purified by column chromatography and thenconcentrated under reduced pressure to provide 6.8 g of Tafluprost (86%yield, 2 steps). HPLC (Phenomenex Luna 5 μm silica) analysis of thecrude product showed that no isomer was detectable, and HPLC (ChiralcelOD-H) analysis of the crude product showed that no enantiomer wasdetectable.

¹H-NMR (400 MHz, CDCl₃):δ 7.293 (dd, 2H), 6.994 (t, 1H), 6.912 (d, 2H),6.101 (dd, 1H), 5.795 (dt, 1H), 5.346-5.421 (m, 2H), 4.994 (heptet, 1H),4.170-4.216 (m, 3H), 4.019 (m, 1H), 2.603 (m, 1H), 2.446-2.462 (m, 2H),2.270-2.354 (m, 1H), 2.256 (t, 2H), 2.030-2.146 (m, 4H), 1.839 (d, 1H),1.572-1.688 (m, 3H), 1.220 (d, 6H)

¹³C-CMR (100 MHz, CDCl₃):δ 173.456, 157.949, 138.630 (t), 130.079,129.581, 128.601, 123.567 (t), 121.793, 118.144 (t), 114.767, 77.910,73.234, 69.461 (t), 67.656, 55.712, 50.507, 42.944, 33.966, 26.597,25.703, 24.808, 21.812, 21.789

The crude Tafluprost could also be purified via silylation anddesilylation as described in Examples 11 and 12. HPLC (Phenomenex Luna 5μm silica) analysis of the crude product showed that no isomer orimpurity was detectable, and HPLC (Chiralcel OD-H) analysis of the crudeproduct showed that no enantiomer was detectable.

¹H-NMR (400 MHz, CDCl₃): δ7.257-7.304 (m, 2H), 6.962-6.999 (m, 1H),6.898-6.923 (m, 2H), 6.003-6.076 (m, 1H), 5.757-5.852 (m, 1H),5.389-5.452 (m, 1H), 5.267-5.330 (m, 1H), 4.985 (heptet, 1H),4.088-4.226 (m, 3H), 3.837-3.892 (m, 1H), 2.495-2.519 (m, 1H),2.163-2.308 (m, 4H), 1.985-2.100 (m, 3H), 1.594-1.740 (m, 3H),1.461-1.512 (m, 1H), 1.21 (d, 6H), 10.887-0.991 (m, 18H), 0.498-0.616(m, 12H)

¹³C-NMR (100 MHz, CDCl₃):δ 173.106, 158.070, 139.329 (t), 129.500,129.333, 129.211, 124.179 (t), 121.644, 118.152 (t), 114.699, 76.428,71.623, 69.544 (t), 67.312, 54.469, 49.323, 45.087, 34.112, 26.704,25.049, 24.859, 21.793, 6.847, 6.688, 4.988, 4.745

Examples 38˜45 Preparation of Isopropyl Unoprostone and itsIntermediates Example 38(3aR,4R,5R,6aS)-4-[3-(tert-butyldimethylsilyloxy)decyl)-5-(tetrahydro-2H-pyran-2-yloxy)hexahydro-2H-cyclopentab]furan-2-ol

A solution of(3aR,4R,5R,6aS)-4-(3-(tert-butyldimethylsilyloxydecyl)-5-(tetrahydro-2H-pyran-2-yloxy)-hexahydro-2H-cyclopenta[b]furan-2-one(29 g, 58.4 mmol) in 300 ml toluene was cooled to −70° C. and followedby dropwise addition of diisobutylaluminium hydride (88 ml, 20% inHexane). The reaction mixture was quenched with 10 ml saturated ammoniumchloride and 150 ml 2M NaHSO₄ while stirring for 30 minutes. Then, themixture was phase separated and the aqueous layer was extracted withtoluene. The organic layers were dried over anhydrous MgSO₄ andconcentrated under reduced pressure to give 32 g of crude product.

¹H-NMR (CDCl₃): δ 4.972˜5.616 (m, 1H), 4.606˜4.754 (m, 2H), 3.501˜4.057(m, 4H), 1.177˜2.300 (m, 28H), 0.826˜0.952 (m, 12H), 0.595 (m, 1H),−0.037˜0.031 (m, 6H)

¹³C-NMR (CDCl₃): δ 106.060 (105.909, 104.649, 104.064, 102.273), 100.550(100.459, 100.147, 99.981), 90.310 (89.976, 89.916, 89.536, 89.437,88.952, 88.899), 87.009 (86.014, 85.513, 85.445, 85.377, 84.314), 76.929(76.845, 76.731, 76.640, 76.541, 76.496, 76.329), 66.735 (66.332,66.211, 65.976), 58.120 (57.254, 56.123, 55.721, 52.343, 52.207, 51.987,51.888, 49.870, 49.687, 49.322, 49.186), 46.734 (46.688, 46.620), 45.474(45.277, 43.994, 42.954), 41.671 (41.565, 41.474, 41.079), 40.707,39.584 (39.546, 39.493, 39.371), 36.244, 35.273 (35.181, 34.885, 34.825,34.627), 34.225 (34.195, 34.104), 33.716, 33.307 (33.223, 33.079,32.973), 30.331, 29.891 (29.800, 29.724, 29.640, 29.602, 29.352),28.206, 24.320 (23.591, 23.500, 23.356), 22.490, 18.521, 11.386 (9.518),0.053

Example 39(Z)-7-[(1R,2R,3R,5)-2-(3-(tert-butyldimethylsilyloxy)decyl)-5-hydroxy-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoicacid

A suspension of (4-carboxybutyl)triphenylohosphonium bromide (102 g,0.23 mol) and potassium tert-butoxide (52 g, 0.46 mol) in THF (700 mL)was cooled to −20° C. in 1-liter round-bottom flask, and a solution of(3aR,4R,5R,6aS)-4-[3-(tert-butyldimethyl-silyloxy)-decyl)-5-(tetrahydro-2H-pyran-2-yloxy)hexahydro-2H-cyclopenta[b]furan-2-ol(32 g from example 38) in 150 ml tetrahydrofuran at −20° C. was addedinto the flask and the reaction mixture was stirred for 4 hours. Thensaturated aqueous solution of ammonium chloride (300 mL) was added andthe resulting suspension was stirred for 30 min at room temperature.Then, the mixture was phase separated and the aqueous layer was adjustedto a pH of 6.0 with 2M sodium bisulfate solution and extracted with 300ml ethyl acetate. The organic layers were combined and dried overanhydrous MgSO₄. The solid was filtered off and organic solvent wasevaporated off under vacuum to obtain 61 g crude product.

¹H-NMR (CDCl₃): δ 5.238˜5.449 (m, 2H), 4.590˜4.662 (m, 1H), 4.067 (m,1H), 3.803˜3.936 (m, 2H), 3.403˜3.531 (m, 2H), 1.897˜2.145 (m, 8H),1.227˜1.859 (m, 26H), 0.844˜0.919 (m, 12H), 0.529˜0.568 (m, 1H), 0.00(m, 6H)

¹³C-NMR (CDCl₃): δ 172.165, 135.337 (133.272), 133.044 (132.923),101.506 (101.400, 100.808, 100.717), 87.441 (87.312, 86.401, 84.815),79.289 (79.213), 77.004 (76.860, 76.769), 67.114 (67.061, 66.575,66.477), 56.298 (56.222, 55.964, 55.941, 54.476, 54.431, 54.385,54.332), 44.988 (44.927), 42.870, 41.550 (41.512, 41.466, 41.428),39.766 (39.667, 39.667, 39.607), 37.959, 35.274, 35, 569 (35.181),34.233 (34.217), 34.043 (33.876), 33.747 (33.663), 31.849 (31.758,31.538, 31.485), 30.992, 30.346, 29.853 (29.807, 29.732), 29.193,27.098, 24.077 (24.024, 23.614, 23.533), 22.612 (22.566), 18.543, 11.401(9.518), 0.038

Example 40(8aR,9R,10R,11aS,Z)-9-[3-(tert-butyldimethylsilyloxy)decyl)-10-(tetrahydro-2H-pyran-2-yloxy)-4,5,8,8a,9,10,11,11a-octahydrocyclo-penta[b]oxecin-2(3H)-one

A solution of(Z)-7-[(1R,2R,3R,5S)-2-(3-(tert-butyldimethyl-silyloxy)decyl)-5-hydroxy-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoicacid (61 g from Example 39) in 250 mL xylene was treated with2,2′-dipyridyl disulfide (36 g, 0.17 mol) and triphenylphosphine (38 g,0.43 mol). This mixture was then stirred for 1 hour at room temperatureunder an atmosphere of nitrogen and the resulting mixture was heated to80° C. for 18 hours. Then, the xylene was removed under reducedpressure, and the residue was diluted with 200 ml saturated sodiumbicarbonate aqueous solution and extracted with 200 ml ethyl acetatetwice. The organic layer was dried over anhydrous MgSO₄. The solid wasfiltered off and organic solvent was evaporated off under vacuum. Thecrude product was purified by chromatography on silica gel using amixture of hexane and ethyl acetate as a gradient eluent. Yield of thetitle compound was 25 g (75% in 3 steps).

¹H-NMR (CDCl₃): δ 5.246˜5.388 (m, 2H), 5.098 (m, 1H), 4.589 (m, 1H),3.459˜3.918 (m, 4H), 1.249˜2.477 (m, 33H), 0.867˜1.021 (m, 12H), 0.579(q, 1H), 0.026 (m, 6H)

¹³C-NMR (CDCl₃): δ 173.751 (173.683), 131.033, 127.709 (127.769),100.459 (100.391, 96.110, 96.011), 84.246 (83.874, 78.857, 78.599),73.528, 72.823 (72.716, 72.572, 72.443), 62.758 (62.151, 62.006),49.399, 44.928 (44.769, 44.640, 44.435), 39.873 (39.835), 37.178(37.140), 37.042 (37.011), 36.017, 34.059 (34.013), 33.884 (33.839),31.812, 31.030, 30.886, 29.831 (29.800), 29.300, 27.288 (27.216), 26.848(26.658, 26.597), 25.907, 25.504 (25.428, 25.353, 25.254, 25.193),22.635, 19.850 (19.311, 19.182), 18.111, 14.073, −4.409

Example 41(8aR,9R,10R,11aS,Z)-9-(3-hydroxydecyl)-10-(tetrahydro-2H-pyran-2-yloxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

A solution of (8aR,9R,10R,11aS,Z)-9-[3-(tert-butyldimethylsilyloxy)decyl)-10-(tetrahydro-2H-pyran-2-yloxy)-4, 5,8,8a,9,10,11,11a-octahydrocyclo-penta[b]oxecin-2(3H)-one (25 g, 44 mmol)in 350 ml tetrahydrofuran and 49 ml TBAF (1M in tetrahydrofuran) wereadded into 1-liter round-bottom flask. The reaction mixture was stirredat 50° C. for 3 hours and quenched by 200 ml saturated NaHCO₃ aqueoussolution. Then, the mixture was phase separated and the aqueous layerwas extracted with ethyl acetate. The organic layers were combined anddried over anhydrous MgSO₄. The solid was filtered off and organicsolvent was evaporated off under vacuum. The crude product was purifiedby chromatography on silica gel using a mixture of hexane and ethylacetate as a gradient eluent. Yield of the titled compound was 15 g(75%).

¹H-NMR (CDCl₃): δ 5.243˜5.322 (m, 2H), 5.109 (m, 1H), 4.565˜4.621 (m,1H), 3.475˜3.947 (m, 3H), 1.275˜2.470 (m, 36H), 0.872 (m, 3H)

¹³C-NMR (CDCl₃): δ173.797 (173.721), 131.132, 127.655, 100.322 (100.338,97.408, 96.922), 84.489 (84.413, 79.950, 79.358), 73.361, 72.185(72.020, 71.995, 71.692), 63.236 (62.834, 62.720), 48.693, 45.383(44.966, 44.860), 39.865 (39.812), 37.717 (37.679), 37.459 (37.429),36.017, 34.552 (34.499, 34.324, 33.960), 31.804, 31.129 (31.038,30.985), 29.702 (29.664, 29.292), 28.085, 27.508, 27.113, 26.817(26.660), 25.687 (25.633), 25.375, 22.643, 19.994 (19.736), 14.088

Example 42(8aR,9R,10R,11aS,Z)-9-(3-oxodecyl)-10-(tetrahydro-2H-pyran-2-yloxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one

(8aR,9R,10R,11aS,Z)-9-[3-hydroxy)decyl)10-(tetrahydro-2H-pyran-2-yloxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(15 g, 33 mmol) was dissolved in 150 ml toluene in 1-liter round-bottomflask. Subsequently, (2,2,6,6-tetramethyl-piperidin-1-yl)oxyl (1.05 g,6.7 mmol), potassium bromide (3.96 g, 33 mmol), 72 ml of 3% NaHCO₃aqueous solution and 26 ml of 12% NaOCl aqueous solution was added intothe flask at 0° C., followed by addition of 300 ml water and 300 mlethyl acetate. The reaction mixture was stirred for 10 minutes. Then,the mixture was phase separated and the aqueous layer was extracted withethyl acetate. The organic layers were combined and dried over anhydrousMgSO₄. The solid was filtered off and organic solvent was evaporated offunder vacuum. The crude product was purified by chromatography on silicagel using a mixture of hexane and ethyl acetate. Yield of the titledcompound was 14 g (94%).

¹H-NMR (CDCl₃): δ 5.184˜5.263 (m, 2H), 5.055 (s, 1H), 4.475˜4.528 (m,1H), 3.413˜3.3.885 (m, 3H), 2.609 (t, 1H), 1.974˜2.537 (m, 11H),1.474˜1.817 (m, 13H), 1.213 (m, 8H), 0.813 (m, 3H)

¹³C-NMR (CDCl₃): δ 211.400 (211.020), 173.653 (173.546), 131.124,127.526, 100.330 (97.013), 84.762, 70.502, 63.031 (62.781), 45.141,44.738, 42.924 (42.879), 40.169 (39.994, 39.843), 37.285, 31.615, 31.129(31.114), 29.193 (29.163), 29.026, 26.969, 26.620, 25.580, 25.444(25.406), 25.337, 33.834, 22.544

Example 43(8aR,9R,10R,11aS,Z)-9-(3-oxodecyl)-10-hydroxy)-4,5,8,8a,9,10,11,11a-octa-hydrocyclopenta[b]oxecin-2(3H)-one

(8aR,9R,10R,11aS,Z)-9-(3-oxodecyl)-10-(tetrahydro-2H-pyran-2-yloxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(14 g, 31 mmol) was dissolved in 140 ml methanol in 1-liter round-bottomflask. p-Toluenesulfonic acid monohydrate (0.3 g, 1.6 mmol) was addedinto this flask at room temperature for 3 hours. Then, the reactionmixture was quenched with 70 ml saturated NaHCO₃ aqueous solution andthe mixture was phase separated and the aqueous layer was extracted withethyl acetate. The organic layers were combined and dried over anhydrousMgSO₄. The solid was filtered off and organic solvent was evaporated offunder vacuum. The crude product was purified by chromatography on silicagel using a mixture of hexane and ethyl acetate as a gradient eluent toobtain 7 g oil compound. The oil was dissolved in ethyl acetate (35 ml)at 0° C. and n-hexane (350 ml) was added while stirring for 12 h. Thesolid was filtrated off and washed with n-hexane to obtain 5.6 g whitecrystalline compound (mp 57˜60° C.).

The x-ray powder diffraction pattern of the crystalline compound hascharacteristic peaks expressed in degrees 2θ at approximately 10.8,14.2, 15.2, 16.2, 17.1, 20.1, 21.2, 21.9, 23.0, 25.3, 37.9, 44.1.

¹H-NMR (CDCl₃): δ 5.224˜5.377 (m, 2H), 5.162 (s, 1H), 3.811 (q, 1H),2.559˜2.652 (m, 2H), 2.238˜2.441 (m, 6H), 1.911˜2.226 (m, 4H),1.811˜1.894 (m, 2H), 1.481˜1.722 (m, 7H), 1.270 (m, 8H), 0.872 (t, 3H)

¹³C-NMR (CDCl₃): δ 211.863, 173.569, 131.261, 127.458, 77.513, 73.999,51.820, 46.249, 42.977, 41.072, 40.298, 36.093, 31.653, 29.193, 29.057,27.394, 26.696, 25.542, 25.421, 23.842, 22.590, 14.058

Example 44(Z)-7-[(R,2R,3R,5S)-3,5-dihydroxy-2-3-oxodecyleyclopentyl]hept-5-enoicacid

(8aR,9R,10R,11aS,Z)-9-(3-oxodecyl)-10-hydroxy)-4,5,8,8a,9,10,11,11a-octahydrocyclopenta[b]oxecin-2(3H)-one(5.5 g, 15 mmol) in 60 ml 2-propanol and 8.5 ml of 3 N potassiumhydroxide aqueous solution in 1-liter round-bottom flask was refluxedand stirred for 2 hours. The mixture was cooled to room temperature andadjusted to a pH of 8.5 with 3 N hydrochloric acid aqueous solution.Subsequently, 2-propanol was removed under reduced pressure and thereaction was diluted with 100 ml saturated NaHCO₃ aqueous solution. Thebasic aqueous solution was extracted with 30 ml ethyl acetate twice andthe aqueous layer was adjusted to a pH of 3 with 3 N hydrochloric acidaqueous solution. Then, the acidic aqueous layer was extracted with 100ml ethyl acetate. The organic layer was dried over anhydrous MgSO₄, thesolid was filtered off and organic solvent was evaporated off undervacuum to obtain 6.5 g crude compound.

Determination of Isomer Content of the Product:

A sample of this product was esterified using K₂CO₃ and 2-iodopropane inDMF. After 2 h at 60° C., water and ethyl acetate were added and themixture was extracted with ethyl acetate. After drying-concentration ofthe extracts, crude isopropyl Unoprostone was obtained. HPLC (PhenomenexLuna 5 μm silica) analysis of the crude product showed that no isomerwas detectable, and HPLC (chiralcel OD-H) analysis of the crude productshowed that no enantiomer was detectable.

¹H-NMR (CDCl₃): δ 5.320˜5.458 (m, 2H), 4.128 (m, 1H), 3.862˜3.870 (m,1H), 2.540˜2.652 (dd, 2H), 2.392 (t, 2H), 2.317 (t, 2H), 2.045˜2.2826(m, 8H), 1.340˜1.9394 (min, 8H), 1.239 (m, 8H), 0.799˜0.880 (m, 3H)

¹³C-NMR (CDCl₃): δ 212.181, 177.956, 129.545, 129.280, 78.394, 74.242,51.873, 51.433, 42.962, 42.400, 41.140, 33.186, 31.645, 293.178, 29.049,27.250, 26.529, 26.423, 24.571, 23.819, 22.574, 14.043

The crude isopropyl Unoprostone could also be purified via silylationand desilylation as described in Examples 11 and 12. HPLC analysis usingODS Hypersil of the product showed that no isomer or impurity wasdetectable. HPLC analysis using Chiralcel OD-H of the product showedthat no enantiomer was detectable.

¹H-NMR (CDCl₃): δ 5.275˜5.427 (m, 2H), 4.923˜4.998 (m, 1H), 4.027-4.055(m, 1H), 3.645˜3.697 (m, 1H), 2.014˜2.533 (m, 12H), 1.430˜1.725 (m, 8H),1.173˜1.232 (m, 14H), 0.817˜0.950 (m, 21H), 0.499˜0.570 (m, 12H)

¹³C-NMR (CDCl₃): δ 211.308, 173.061, 129.829, 129.067, 76.709, 71.434,67.259, 49.528, 48.275, 44.374, 42.826, 40.769, 34.142, 31.630, 29.201,29.034, 26.711, 26.559, 25.611, 24.950, 23.895, 22.544, 21.762, 13.959,6.794, 4.942, 4.897

Example 45 (Z)-isopropyl7-(1R,2R,3R,5S)-3,5-dihydroxy-2-(3-oxodecylcyclopentyl)-hept-5-enoate

A solution of(Z)-7-[(1R,2R,3R,5S)-3,5-dihydroxy-2-3-oxodecylcyclo-pentyl]hept-5-enoicacid (6.5 g) was dissolved in 60 ml N,N-dimethylformamide in 250 mlround-bottom flask, followed by addition of potassium carbonate (6.2 g,45 mmol) and 2-iodopropane (5.1 g, 30 mmol). The reaction mixture washeated to 80° C. and stirred for 2 hours. The mixture was cooled to roomtemperature and the solid was filtered off. The filtrate wassubsequently extracted with 100 ml ethyl acetate and 100 ml water. Themixture was phase separated and the organic layer was dried overanhydrous MgSO₄, the solid was filtered off and organic solvent wasevaporated off under vacuum. The crude product was purified bychromatography on silica gel using a mixture of hexane and ethyl acetateas a gradient eluent. Yield of the title compound was 2.4 g (37.7% in 2steps). HPLC (Phenomenex Luna 5 μm silica) analysis of the crude productshowed that no isomer was detectable, and HPLC (chiralcel OD-H) analysisof the crude product showed that no enantiomer was detectable.

¹H-NMR (CDCl₃): δ 5.362˜5.409 (m, 2H), 4.942˜4.985 (m, 1H), 4.126 (m,1H), 3.851 (m, 1H), 1.901˜3.061 (m, 12H), 1.181˜1.778 (m, 24H), 0.843(m, 3H)

¹³C-NMR (CDCl₃): δ 211.513, 173.402, 129.629, 129.181, 78.500, 74.288,67.578, 52.268, 51.615, 42.955, 42.560, 14.224, 34.028, 31.637, 29.178,29.034, 07.372, 26.666, 26.613, 24.897, 23.834, 22.559, 21.808, 14.028

Examples 46˜54 Preparation of Bimatoprost and its Intermediates Example46(3aR,4R,5R,6aS)-hexahydro-4-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-5-(tetrahydro-2H-pyran-2-yloxy)cyclopenta[b]furan-2-one

p-Toluenesulfonic acid monohydrate (0.3 g, 0.165 mmol) was added to asolution of(3aR,4R,5R,6aS)-hexahydro-5-hydroxy-4-((S,E)-3-hydroxy-5-phenylpent-1-enyl)cyclopenta[b]furan-2-one(10.0 g, 33.1 mmol) and 3,4-dihydro-2H-pyran (4.2 g, 49.7 mmol) indichloromethane (100 mL) at room temperature and the mixture was stirredfor 2.5 hr (TLC monitoring). Saturated aqueous solution of sodiumbicarbonate (100 mL) was poured into the reaction mixture and themixture was stirred for 5 minutes. The organic layer was separated andthe aqueous layer was extracted with ethyl acetate (100 mL). Thecombined organic layers were dried over magnesium sulfate, the solid wasfiltered off and the filtrate was concentrated under reduced pressure togive 16.0 g of crude product. The crude product was purified by columnchromatography and then concentrated under reduced pressure to provide14.0 g of the title compound (89.9% yield).

¹H-NMR (CDCl₃): δ 7.117˜7.239 (m, 5H), 5.319˜5.610 (m, 2H), 4.857˜4.982(m, 1H), 4.578˜4.693 (m, 2H), 4.062˜4.123 (m, 1H), 3.755˜3.858 (m, 2H),3.398˜3.481 (m, 2H), 2.328˜2.771 (m, 7H), 1.418˜2.182 (m, 16H)

Example 47(3aR,4R,5R,6aS)-hexahydro-4-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-5-(tetrahydro-2H-pyran-2-yloxy)-2H-cyclopenta[b]furan-2-ol

(3aR,4R,5R,6aS)-hexahydro-4-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-5-(tetrahydro-2H-pyran-2-yloxy)cyclopenta[b]furan-2-one(14.0 g from Example 46) was dissolved in toluene (140 mL), followed bycooling to −70° C., and DIBAL (1.0M in Hexane, 45 mL) was addeddropwisely. Then the reaction was quenched by adding saturated aqueoussolution of ammonium chloride (10 mL) at −70° C. The resulting mixturewas poured into 90 mL of a 2M sodium bisulfate aqueous solution at roomtemperature and stirring was continued for 30 minutes. After separationof the organic layers, 200 mL of toluene was added to the aqueous layer.The combined organic layers were concentrated under reduced pressure togive 18.0 g of crude title compound.

¹H-NMR (CDCl₃): δ 7.136˜7.257 (m, 5H), 5.371˜5.540 (m, 3H), 4.566˜4.703(m, 3H), 3.712˜4.112 (m, 4H), 3.326˜3.470 (m, 2H), 2.177˜2.699 (m, 6H),1.423˜2.085 (m, 17H)

Example 487-((1R,2R,3R,5S)-5-hydroxy-2-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoicacid

A suspension of (4-carboxybutyl)triphenylohosphonium bromide (52.8 g,119 mmol) and potassium-tert butoxide (26.8 g, 238 mmol) in THF (400 mL)was cooled to −20° C. for 30 min. And a solution of(3aR,4R,5R,6aS)-hexahydro-4-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-5-(tetrahydro-2H-pyran-2-yloxy)-2H-cyclopenta[b]furan-2-ol(18 g from Example 47) in 50 mL of THF at −20° C. was added and thereaction mixture was stirred for 16 hr. Then saturated aqueous solutionof ammonium chloride (200 m L) was added and the resulting suspensionwas stirred for 30 min at room temperature. After separation of theorganic layers, the aqueous layer was adjusted to a pH of 6.0 byaddition of a 2M sodium bisulfate solution and extracted with 200 mL ofethyl acetate. The combined organic layers were dried over magnesiumsulfate and concentrated under reduced pressure to give 32.0 g of crudetitle compound.

¹H-NMR (CDCl₃): δ 7.349˜7.430 (m, 2H), 7.041˜7.155 (m, 3H), 5.270˜5.537(m, 4H), 4.620˜4.688 (m, 2H), 3.745˜4.048 (m, 3H), 3.379˜3.554 (m, 4H),2.404˜2.688 (m, 7H), 0.810˜2.179 (m, 21H)

Example 49(6Z,8aR,9R,10R,11aS)-4,5,8,8a,9,10,11,11a-octahydro-9-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-10-(tetrahydro-2H-pyran-2-yloxy)cyclopenta[b]oxecin-2(3H)-one

A solution of7-((1R,2R,3R,5S)-5-hydroxy-2-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enoicacid (32 g from example 48) in 320 mL dichloromethane was treated withN,N-diisopropyl-ethylamine (12.3 g, 94.8 mmol) and benzoyl chloride (7.9g, 56.3 mmol. This mixture was then stirred for 10 minutes at roomtemperature under an atmosphere of nitrogen, followed by addition of4-(dimethylamino)-pyridine (11.9 g, 97.7 mmol) at 0° C. while stirringfor 10 minutes. The resulting mixture was quenched with a saturatedsodium bicarbonate solution (300 mL) and extracted with dichloromethane(100 mL). The organic layer is dried over magnesium sulfate andconcentrated under reduced pressure to give 29.0 g of crude product. Thecrude product was purified by column chromatography providing 9.4 g ofthe title compound (58.6% yield, 3 steps).

¹H-NMR (CDCl₃): δ 7.110˜7.307 (m, 5H), 5.185˜5.508 (m, 5H), 4.651˜4.754(m, 2H), 3.837˜4.148 (m, 4H), 3.418˜3.472 (m, 2H), 2.186˜2.750 (m, 9H),1.542˜2.131 (m, 19H)

Example 50(5Z)—N-ethyl-7-((1R,2R,3R,5S)-5-hydroxy-2-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enamide

A solution of(6Z,8aR,9R,10R,11aS)-4,5,8,8a,9,10,11,11a-octahydro-9-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-10-(tetrahydro-2H-pyran-2-yloxy)cyclopenta[b]oxecin-2(3H)-one(3.0 g, 5.57 mmol) in 15 mL tetrahydrofuran (THF) was treated with 2 Methylamine (31 ml) in THF. This mixture was stirred and heated at 40° C.over 18 hours under an atmosphere of nitrogen. The mixture was dilutedwith 50 mL water and the pH was adjusted to 6 with IN HCl. The layerswere separated and the aqueous layer was extracted with 20 mL ethylacetate twice. The organic layer is dried over magnesium sulfate andconcentrated under reduced pressure. Then, the crude product waspurified by column chromatography providing 2.4 g of the title compound(73.8% yield).

¹H-NMR (CDCl₃): δ 7.148˜7.284 (m, 5H), 5.364˜5.596 (m, 5H), 4.669˜4.721(m, 2H), 4.048˜4.122 (m, 3H), 3.777˜3.869 (m, 2H), 3.459 (m, 2H), 3.235(m, 2H), 1.906˜2.748 (m, 11H), 1.503˜1.810 (m, 8H), 1.095 (t, 3H)

¹³C-NMR (CDCl₃): δ 172.863, 142.160, 136.164, 135.860, 131.397(131.352), 129.948 (129.894), 129.044 (129.006), 128.354, 125.758,98.174 (96.178), 94.630 (94.508), 82.288 (80.959), 75.388 (75.335),73.240 (72.754), 62.773 (62.226), 62.097 (61.589), 53.232 (52.989),50.590 (50.454), 41.543, 39.660, 37.619 (37.573), 35.979, 34.264,32.123, 31.607, 30.802, 30.635, 26.711, 25.656, 25.557, 25.451 (25.368),19.683 (19.531, 19.478, 18.08), 14.885

Example 51 Bimatoprost

p-Toluenesulfonic acid monohydrate (0.03 g, 0.17 mmol) was added to astirred solution of(5Z)—N-ethyl-7-((1R,2R,3R,5S)-5-hydroxy-2-((S,E)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-3-(tetrahydro-2H-pyran-2-yloxy)cyclopentyl)hept-5-enamide (2.0 g, 3.4 mmol) in methanol (20 mL).The mixture was stirred for 2 hours at room temperature. Then, thereaction mixture was washed with saturated aqueous solution of sodiumbicarbonate (50 mL). The layers were separated and the aqueous layer wasextracted with ethyl acetate (20 mL). The organic layers were dried overmagnesium sulfate, filtered and concentrated under reduced pressure. Theresidue was crystallized from hexane and ethyl acetate to giveBimatoprost in a white crystalline form (77.5% yield). UPLC (ACQUITYUPLC BEH C18) analysis of the crude product showed that no 5,6-transisomer, 15β-isomer or any other isomers were found.

¹H-NMR (CDCl₃): δ 7.153˜7.279 (m, 5H), 5.812 (m, 1H), 5.319˜5.610 (m,4H), 4.055˜4.128 (m, 2H), 3.910 (m, 1H), 3.863˜3.876 (m, 1H),3.287˜3.440 (m, 2H), 3.195˜3.250 (m, 2H), 2.618˜2.716 (m, 2H),1.429˜2.365 (m, 14H), 1.093 (t, 3H)

¹³C-NMR (CDCl₃): δ 173.252, 142.001, 135.030, 133.093, 129.695, 129.120,128.410, 128.333, 125.756, 77.773, 72.416, 72.189, 55.573, 50.297,42.912, 38.738, 35.827, 34.352, 31.862, 26.663, 25.590, 25.367, 14.781

Example 52(6Z,8aR,9R,10R,11aS)-4,5,8,8a,9,10,11,11a-octahydro-10-hydroxy-9-((S,E)-3-hydroxy-5-phenylpent-1-enyl)cyclopenta[b]oxecin-2(3H)-one

p-Toluenesulfonic acid monohydrate (0.16 g, 0.84 mmol) was added to astirred solution of(6Z,8aR,9R,10R,11aS)-4,5,8,8a,9,10,11,11a-octahydro-9-((SE)-5-phenyl-3-(tetrahydro-2H-pyran-2-yloxy)pent-1-enyl)-10-(tetrahydro-2H-pyran-2-yloxy)cyclopenta[b]oxecin-2(3H)-one(9.0 g, 16.7 mmol) in methanol (90 mL). The mixture was stirred for 2 hrat room temperature (TLC monitoring). Then, the reaction mixture waswashed with saturated aqueous solution of sodium bicarbonate (100 mL).The organic layer was separated and the water layer was extracted withethyl acetate (100 mL). The combined organic layers were dried overmagnesium sulfate, filtered and concentrated under reduced pressure togive 9.0 g of crude product. The crude product was purified by columnchromatography providing 3.5 g of the title compound (56.5% yield).

¹H-NMR (CDCl₃): δ 7.249˜7.285 (m, 2H), 7.155˜7.189 (m, 3H), 5.613˜5.671(m, 1H), 5.294˜5.416 (m, 2H), 4.040˜4.135 (m, 2H), 3.754 (q, 1H), 3.657(br s, 1H), 3.311 (br s, 1H), 2.555˜2.691 (m, 3H), 2.319˜2.398 (m, 3H),2.159˜2.290 (m, 2H), 2.094˜2.111 (m, 2H), 1.542˜1.960 (m, 8H)

Example 53(5Z)-7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((S,E)-3-hydroxy-5-phenylpent-1-enyl)cyclopentyl)hept-5-enoicacid

A solution of(6Z,8aR,9R,10R,11aS)-4,5,8,8a,9,10,11,11a-octahydro-10-hydroxy-9-((S,E)-3-hydroxy-5-phenylpent-1-enyl)cyclopenta[b]oxecin-2(3H)-one(2 g, 5.4 mmol) in 20 ml 2-propanol and 6.3 ml of 3 N potassiumhydroxide aqueous solution in 50 mL round-bottom flask was refluxed andstirred for 2 hours. The mixture was cooled to room temperature andadjusted to a pH of 8.5 with 3 N hydrochloric acid aqueous solution.Subsequently, the 2-propanol was removed under reduced pressure andresulting mixture was diluted with 30 ml saturated NaHCO₃ aqueoussolution. The basic aqueous solution was extracted with 30 ml ethylacetate twice and the aqueous layer was adjusted to a pH of 3 with 3 Nhydrochloric acid aqueous solution. Then, the acidic aqueous layer wasextracted with 50 ml ethyl acetate. The organic layer was dried overanhydrous MgSO₄, the solid was filtered off and organic solvent wasevaporated off under vacuum to obtain 2 g of the crude title compound.

¹H-NMR (CDCl₃): δ 7.160˜7.253 (m, 5H), 5.327˜5.589 (m, 4H), 4.012 (m,2H), 3.904 (m, 2H), 1.265˜2.656 (m, 18H)

¹³C-NMR (CDCl₃): δ 177.626, 141.832, 134.840, 133.160, 129.626, 129.107,128.397, 128.351, 125.794, 77.412, 72.397, 72.305, 55.183, 49.977,42.634, 38.443, 33.023, 31.794, 26.252, 25.176, 24.458

Example 54 (5Z)-methyl7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((S,E)-3-hydroxy-5-phenylpent-1-enyl)cyclopentyl)hept-5-enoate

A solution of (5Z)-7-((1R,2R,3R,5S)-3,5-dihydroxy-2-((S,E)-3-hydroxy-5-phenylpent-1-enyl)cyclopentyl)hept-5-enoicacid (2 g from Example 53) was dissolved in 20 ml N,N-dimethylformamidein 50 mL round-bottom flask, followed by addition of potassium carbonate(2.2 g, 16.2 mmol) and iodomethane (1.1 g, 8.1 mmol). The reactionmixture was heated to 40° C. and stirred for 2 hours. The mixture wascooled to room temperature and the solid was filtered off. The filtratewas subsequently diluted and extracted with 20 ml ethyl acetate and 20ml water. The mixture was phase separated and the organic layer wasdried over anhydrous MgSO₄, the solid was filtered off and organicsolvent was evaporated off under vacuum. The crude product was purifiedby chromatography on silica gel using a mixture of hexane and ethylacetate as a gradient eluent. Yield of the title compound was 1.6 g(73.5% in 2 steps)

¹H-NMR (CDCl₃): δ 7.183˜7.268 (m, 5H), 5.371˜5.608 (m, 4H), 4.091˜4.153(m, 2H), 3.916 (m, 1H), 3.639 (s, 3H), 2.686 (m, 3H), 1.487˜2.686 (m,16H)

¹³C-NMR (CDCl₃): δ 177.345, 141.886, 135.084, 133.067, 129.655, 129.027,128.398, 128.349, 125.796, 77.820, 72.648, 72.227, 55.672, 51.566,50.205, 42.840, 38.745, 33.360, 31.813, 26.581, 25.4716, 24.744

1. Latanoprost containing a non-detectable level of 5,6-trans isomer and15β-isomer as determined by HPLC method, the limit of detection of HPLCmethod being more than 0.02%.
 2. Travoprost containing a non-detectablelevel of 5,6-trans isomer and 15β-isomer as determined by HPLC method,the limit of detection of HPLC method being more than 0.02%. 3.Tafluprost containing a non-detectable level of 5,6-trans isomer asdetermined by HPLC method, the limit of detection of HPLC method beingmore than 0.02%.
 4. Isopropyl Unoprostone containing a non-detectablelevel of 5,6-trans isomer as determined by HPLC method, the limit ofdetection of HPLC method being more than 0.020%.